Correct option is D
The correct answer is:
(d) pitch in
This phrase means to contribute to a group effort, which fits the context of neighbors helping to renovate the community garden.
Here are the meanings of the incorrect options:
(a)
get in - To enter a place or become involved in an activity.
(b)
put in - To interrupt in a conversation or discussion.
(c)
catch in - to capture or seize especially after pursuit that doesn't make sense in this context.
(e)
take in - To absorb or understand information, or to experience something.