grammar question--- is the underlined word used correctly

Question

I have recommended your book to all my friends which drive trucks.

a.) who

b.) whose.

c.) whom

d). correct as is

I understand that b is incorrect but I don't know the correct answer. Could someone help me understand what is correct and why?

Answer 1

The subordinating conjunctions, including chronological or time-order, including after, before, once, since, until, when, whenever, while;

the contrast or on "on the contrary," however, although, though, whereas;

the result/effect or in order that, so, so that;

the reason/cause as or because or since;

condition or subjunctive case--"If only I were a king!" or even if, provided that, unless, if;

choice or rather than, than, whether (or not)

and location or where, whereas, act as transition markers and ensure coherence, unity, and balance in a college-level or extended essay.

Likewise, conjunctive adverbs provide coherence, unity, and balance, including chronological or time order next, then, meanwhile, finally subsequently;

the contrast, or however, still, nevertheless, conversely, nonetheless, instead, otherwise;

result/summary or therefore, thus, consequently, accordingly, hence, then;

comparison or similarly, likewise; emphasis or indeed and certainly;

addition or also, furthermore, moreover, besides

These act to ensure coherence, unity, and balance.

Transitional phrases are very important for well-written essays and are required for logic, clarity, and fluency.

Answer 2

Lily's answer above is correct and thorough. One little trick to see if a pronoun should be in a subject or object form is 1. If the pronoun is followed by a verb, it's a subject, as in "...who drive trucks." if it's followed by a noun or pronoun, it is likely an object, as in "The brother whom I love is very ill." (You test drive this by rephrasing to say, "I love him." (Not he--a subject). Whose is possessive, and which doesn't properly refer to people.

Part of students' confusion with pronouns results from so many people, including teachers, misusing them so often.

Answer 3

The question is asking for the correct relative pronoun inside the relative clause.

B is incorrect because it is a possessive pronoun, but there's no possessive in this sentence (the trucks don't necessarily belong to my friends).

C is incorrect because this pronoun is used for objects, but my friends is the subject of the relative clause (my friends are the ones who drive the trucks).

D is incorrect because "which" is used for things, not people.

A is the correct answer. This is a subject relative pronoun used for people, which makes sense because "my friends" is the subject of this relative clause.