Select the most appropriate option to substitute the highlighted segment in the given sentence.
Vishnu was happy to push the boat out for his fiancée’s birthday.

Correct option is C

The correct substitution of the highlighted segment is “to spend a lot of money because he was celebrating.”
Error identification: The phrase "push the boat out" is an idiom meaning to spend a lot of money on a celebration.
Grammatical Rule used: The idiom must be understood in its figurative sense and correctly expressed in a way that matches the context of celebration.
Corrected sentence: Vishnu was happy to spend a lot of money because he was celebrating his fiancée’s birthday.