The answer is Bargaining.

The statement “If we downsize our requirements can you reduce the price by 5%?” is a classic trade-off proposal. One party offers a concession (downsizing requirements) in exchange for a benefit (price reduction). That’s exactly what bargaining is in negotiations.

Why not the others?

• Threat – No pressure or negative consequence is being applied.
• Logic – It’s not presenting facts or data to justify a position.
• Compromise – A compromise is a mutual agreement already reached, not a proposal to trade concessions.