Which of the options, (a), (b), (c), (d) given below each sentence should replace the phrase printed in bold in the sentence to make sentence grammatically correct? If the sentence is already grammatically correct, mark option ‘No replacement required’ as the answer.
Despite the rain, a number of students has showed up to the outdoor event.

Correct option is A

The given phrase in the bold is incorrect. The expression ‘a number of’ is always followed by a plural noun and a plural verb.
Explanation in Detail:
"A number of":
Meaning: It signifies an unspecified or non-specific quantity or amount. It implies that there is more than one of something, but the exact number is not specified.
Usage: It is typically followed by a plural noun and a plural verb.
For example:
A number of students attended the seminar.
A number of cars were parked in the lot.
"The number of":
Meaning: It refers to a specific, known, or countable quantity or amount. It indicates that a specific number is being referred to, and that number is usually specified in the sentence.
Usage: It is often followed by a singular noun and a singular verb.
For example:
The number of participants in the marathon was 500.
The number of books on the shelf is decreasing.
Therefore, the correct replacement is ‘students have showed up’. All other options are grammatically incorrect.