A sentence has been split into four parts: (A), (B), (C), and (D). Determine which section contains a grammatical mistake. If the sentence is completely correct as written, choose “No error” as your answer.

He prefers cycling through the countryside, (A)/ kayaking down the river, (B)/ and to photograph wildlife (C)/ on his weekend getaways. (D)

The correct option is C.

Explanation:
The sentence presents a list of three activities that the subject prefers doing on weekend getaways:
1. cycling through the countryside (gerund phrase)
2. kayaking down the river (gerund phrase)
3. to photograph wildlife (infinitive phrase)

To maintain parallel structure (parallelism) in English grammar, all items joined in a series or list following a verb (here, prefers) must share the same grammatical structure. Since the first two items are expressed as gerunds (cycling, kayaking), the third item should also be expressed as a gerund (photographing) instead of an infinitive (to photograph).

Corrected Sentence:
"He prefers cycling through the countryside, kayaking down the river, and photographing wildlife on his weekend getaways."

Therefore, section (C) contains the grammatical mistake.