Source: Veritas

When the SARS (Severe Acute Respiratory Syndrome) pandemic occurred in late 2002, officials feared that the outbreak would widespread; they were concerned that the virus would become a global threat and it would kill vast numbers of patients who would have no protection against it.

(A) it would kill vast numbers of patients who would have no protection against it.
(B) it would kill vast numbers of patients with no protection against it.
(C) kill vast numbers of patients who would have no protection against it.
(D) kill vast numbers of patients who have no protection against them.
(E) kill vast numbers of patients with no protection against them.


we can eliminate D and E since they use them to refer virus.
with no protection does not modify patients as additional information without a comma in between them and

Noun modifiers are often introduced by Relative Pronouns such as the following:
Which That Who Whose Whom Where When
Such modifiers are called Relative Pronouns. Relative pronouns are subject to several restrictions.
The pronouns who and whom must modify people.
the pronoun which must modify things
that cannot modify people
whose can modify either people or things,
Thus B is wrong since we use with to modify patients.

I read in solution that for A to be correct that needs to be placed before it. since it is not present A is wrong.
Can someone explain that scenario for me and also explain why C is correct?