What is the next-best option?

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</style></head><body><main><header><p class="kicker">CHOICE LAB · ONE TEN-MINUTE SLOT</p><h1>What is the next-best option?</h1><p>Every activity uses the whole ten-minute slot. Choose exactly one feasible option; then identify the best remaining one.</p></header><div class="actions"><button type="button" id="round1">R1</button><button type="button" id="round2">R2</button><button type="button" id="round3">R3</button></div><section class="panel"><h2>Feasibility and supplied preference</h2><div id="round" class="result" role="status" aria-live="polite"></div><div class="actions"><button type="button" id="A">A · Paper model</button><button type="button" id="B">B · Poster sketch</button><button type="button" id="C">C · Silent puzzle</button></div><div id="choice" class="result" role="status" aria-live="polite">No choice yet.</div></section><section class="panel"><h2>Name what was forgone</h2><label for="nextBest">Next-best feasible alternative ID</label><input id="nextBest" type="text" value=""><label for="reason">Explain the ranking, constraint and forgone benefit</label><textarea id="reason" rows="4"></textarea><div class="actions"><button type="button" id="check">Check conditional alternative</button><button type="button" id="reveal">Reveal conditional key</button><button type="button" id="reset">Reset rounds</button></div><div id="feedback" class="result" role="status" aria-live="polite">Choose a feasible activity.</div><div id="key" class="strip" hidden></div></section><footer>Opportunity cost follows the highest-ranked remaining feasible activity for the choice you made.</footer><noscript>JavaScript is required for the local controls. The accompanying article contains worked examples.</noscript></main><script>
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const rankings=[['A','B','C'],['C','A','B'],['B','C']];let i=0,choice='';function clear(){$('nextBest').value='';$('reason').value='';$('key').hidden=true;$('feedback').textContent='Choose a feasible activity and explain the next-best alternative.';}function show(n){i=n;choice='';$('round').textContent='R'+(i+1)+' · Feasible: '+rankings[i].join(', ')+' / Ranking: '+rankings[i].join(' > ')+' / One ten-minute slot.';$('A').disabled=i===2;$('choice').textContent='No choice yet.';clear();}rankings.forEach((_,n)=>$('round'+(n+1)).addEventListener('click',()=>show(n)));['A','B','C'].forEach(id=>$(id).addEventListener('click',()=>{if(!rankings[i].includes(id))return;choice=id;$('choice').textContent='Chosen: '+id;clear();}));['nextBest','reason'].forEach(id=>$(id).addEventListener('input',()=>{$('feedback').textContent='Answer changed. Check again.';$('key').hidden=true;}));const key=()=>rankings[i].find(id=>id!==choice);$('check').addEventListener('click',()=>{$('feedback').textContent=!choice||!$('nextBest').value.trim()||!$('reason').value.trim()?'Select one feasible choice, an alternative ID and a reason.':$('nextBest').value.trim().toUpperCase()===key()?'Matches the conditional next-best alternative: '+key()+'. Teacher reviews your reasoning; no desirability score.':'Revisit the highest-ranked remaining feasible option. Do not add all alternatives together.';});$('reveal').addEventListener('click',()=>{if(!choice){$('feedback').textContent='Choose one feasible activity before revealing a key.';return;}$('key').hidden=!$('key').hidden;$('key').textContent='Choice '+choice+' → next-best feasible alternative '+key()+'. Chosen benefit is separate from forgone benefit.';});$('reset').addEventListener('click',()=>show(0));show(0);
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