You should use "take" in the following sentence:
c. The group **take** their cars to work every day.
Here's why:
In British English, collective nouns like "group," "team," or "staff" are often treated as plural when the individuals in the group are acting separately or individually. Therefore, "group" can be followed by "take" to indicate that the members of the group each take their own car to work.
In contrast, American English would typically use "takes" for collective nouns in most contexts, regardless of whether the individuals are acting collectively or separately. However, the correct answer here is based on British English usage.
The other sentences all use singular collective nouns (chorus, crew, army) where the action is done by the group as a whole, so "takes" is appropriate:
a. The school chorus **takes** a bow at the end of the recital.
b. The grounds crew **takes** a break during the morning.
d. The army **takes** its positions on the battlefield.