Unlike all the other mammal species whose olfactory receptors, which

In option 'A' can 'which' refer to 'objects'?
From what I have understood, relative pronoun modifier need not always modify the noun preceding it. It depends on the context. It can jump prepositional phrase, like in this case 'to smell various objects', and refer to far away noun-'olfactory genes'.
Here, it would be illogical to say ' objects in turn detect their odor' .
Am I correct in my analysis?
What exactly is the issue with option A?

Whenever you see which, it’s a good idea to consider what it most logically modifies. Typically, it’s the closest noun. I’d argue that the noun-modifier "which" most directly modifies "objects" in this sentence. This makes it seem like the object is detecting the odor of the olfactory genes.

You’re correct that this does not have to be the case!

In this scenario, though, the original sentence includes “which in turn.” Even if “which” was modifying “olfactory genes,” which in turn logically shifts the focus.

Does this make sense?

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To add to this, relative modifiers can jump prepositional phrases, but only when those prepositional phrases are part of a noun phrase, and when the relative clause describes the noun phrase as a whole. So for instance, if I said, "the bench under the tree, which was recently painted", "which was recently painted" could describe "the tree" OR "the bench (under the tree)" — logically, it makes more sense for a bench to be recently painted than for a tree to be recently painted, so we would assume that "the bench (under the tree)" was the subject.

However, in this sentence, we do not have a noun phrase. The prepositional phrase "to smell various objects" does not describe "olfactory genes" — it describes the verb "use". So "which in turn detect their odor" cannot describe "olfactory genes (to smell various objects)" because it isn't a noun phrase, and relative clauses must describe either nouns or noun phrases that they are next to. So it has to describe noun "objects", which creates an illogical sentence.

While relative clauses are tricky, they still follow the rule that they must be next to the noun/noun phrase they describe. Relative clauses' ability to jump prepositional phrases only follows from the fact that they can describe noun phrases, and thus they can jump the prepositional phrase portion of the noun phrase to describe the subject of the noun phrase. However, if the prepositional phrase is not part of a noun phrase that the relative clause is describing, the relative clause cannot jump the prepositional phrase.

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