Is the verb transitive intransitive or linking in the sentence The rabbit munched the lettuce?

The verb in the sentence, 'munched' is a transitive verb, a verb that takes an object.

An intransitive verb requires no object, for example: The rabbit munched the lettuce and slept. (no object required for the verb 'slept')

The easy way to recognize a linking verb is that a linking verb acts as an equals sign, the object is a form of the subject (The rabbit is white. rabbit=white); or the subject becomes the object (The rabbit got wet. rabbit->wet).

The rabbit is not and does not become the lettuce.