Which group lists only examples of linking verbs?

A linking verb joins a subject to a subject complement (also called a predicate noun or predicate adjective), a word or phrase that describes or explains the subject.
The most common linking verb is the verb 'to be'.
- Kayaking is my favourite sport.
- My grandmother was an expert pilot.
Source: Cliffs notes

In these options, all the verbs stated only in b) are linking verbs.