Question

You ..................... stop your vehicles when the traffic lights are red.

• A. could
• B. may
• C. must
• D. would

Answer 1

Answer:

C. must

• Must is used to show obligation / rule / necessity.

• Traffic rules are compulsory, not optional.

Why the others are wrong:

• ❌ could – shows possibility or ability

• ❌ may – shows permission

• ❌ would – shows habit or condition