chef : cooks is the set that completes the analogy because it matches with thief : steals.
In both cases, the first element of the set is the doer of the action, and the second element is the action itself. The rest of the sets do not follow this same pattern.
plants : gardener refers to a noun, and the doer of the action that involves the noun.
mows : grass refers to an action and a noun that is involved in the action.
hopes : faith are two nouns of equal category that may be considered synonyms, depending on the context.