alternative plan; counterproposal
A formal term for a plan or proposal offered as an alternative to an existing one, often in business or policy contexts.
At the meeting, two alternative plans were presented in addition to the original proposal.
As a counterproposal to the budget cuts, streamlining of operations was suggested.
対案 specifically refers to a counterproposal made in direct opposition to another proposal, often in political or formal debate settings.
Compound of 代替 (だいたい, 'substitution; alternative') and 案 (あん, 'plan; proposal').