Which of the following is the best definition of a modal verb?

An auxiliary verb that expresses meanings like possibility, permission, or ability.

Rewrite the following sentence using a modal verb to express a high degree of certainty: 'It is very likely that he is the team's best player.'

He must be the team's best player.

'May' suggests a higher level of possibility than 'might'.

I could visit my family if I have enough money.

I can use modal verbs to express varying degrees of possibility and probability.

1
Modals are auxiliary verbs that help to support the main verb in a sentence and express meanings such as ability, permission, or possibility.
2
The modal verb might is used to express a lower level of possibility or uncertainty, while may expresses a higher level of possibility or permission.
3
The modal verb must is used to express a strong possibility or certainty about something.