Group is the subject. So the verb should be singular. believes is the right verb B, D and E are out.

Ans A over C because C has could at the end and so does not maintain ||ism

As "a group of students" is singular so we have only two choices A and C. In option C could not violets the parallelism rule.
OA please?

What would be the right sentence:

A group of students is walking. or
A group of students are walking.

I understand the singular form "group", but in the sentence it comes as a group of students who "have" suggesting plural form as against "has' which would suggest singular form.

how then to make a call for subject verb agreement.

here2win wrote:What would be the right sentence:

A group of students is walking. or
A group of students are walking.

I understand the singular form "group", but in the sentence it comes as a group of students who "have" suggesting plural form as against "has' which would suggest singular form.

how then to make a call for subject verb agreement.

First try to remember these rules I picked up from one of the Ron's posts.

One of the Xs that/who <plural>
One of the Xs <singular>
only One of the Xs
only One of the Xs that/who <plural>
THE only One of the Xs that/who <singular>

the question is a case similar to the rule (1).


<<RON's Explantion>

one of the birds (that fly) over my house at night.

what that fly is trying to modify is just the <birds> and not <one of the birds>

notice that the RED-COLORED RELATIVE PRONOUN (WHO/THAT) is absolutely crucial here.
if that isn't there - i.e., if "one of the NOUNs" is actually the SUBJECT of the ____ verb - then you take a singular verb instead.
example:
one of the birds flies over the house; the other one flies past it.

In your case below -

A group of students who ....

who is modifying just the students and not <group of students> hence have is used.

However the subject for the verb <believe> is <group of students> which is singular.

Hope this helps.