Fill in the blanks with the most appropriate option:-

We ______ follow the rules of Traffic.

must

The correct option to fill in the blanks is must.

The sentence is about a requirement or obligation to follow the rules of traffic. The modal verb "must" is used to express obligation or necessity. It is the most appropriate modal verb to use in this context, as it describes the fact that it is mandatory to follow the rules of traffic.

The other options are not as appropriate:

• Can is used to express ability or possibility. It is not as appropriate as "must", as it does not convey the same sense of obligation or necessity.
• Could is used to express possibility or ability in the past. It is not as appropriate as "must", as it does not convey the same sense of presentness or immediacy.
• Would is used to express a polite request or a hypothetical situation. It is not as appropriate as "must", as it does not convey the same sense of urgency or importance.