Neanderthals had a vocal tract that resembled those of the apes and so

Neanderthals had a vocal tract that resembled those of the apes and so were probably without language, a shortcoming that may explain why they were supplanted by our own species.

Option Elimination -

(A) Neanderthals had a vocal tract that resembled those of the apes - "a vocal tract" singular compared with plural (those). Moreover, "the" limits to certain apes. Wrong.

(B) Neanderthals had a vocal tract resembling an ape’s - "vocal tract" is compared with ape's (vocal tract). Moreover, "a" general vocal tract is compared with "an" general vocal tract of any ape. Ok. "resembling" is an ING modifier which, when placed without a comma, modifies the noun before it, i.e., "vocal tract" in this case. ok

(C) The vocal tracts of Neanderthals resembled an ape’s - more significant issue - "vocal tracts ..were without language." Wrong. "the" specific Neanderthal vocal tracts are compared with "an" general ape's vocal tract.

(D) The Neanderthal’s vocal tracts resembled the apes’ - more significant issue - "vocal tracts ..were without language." "The Neanderthal’s vocal tracts" specific "Neanderthal" vocal tracts (not one tract) compared with the apes’ - multiple specific apes vocal tracts.

(E) The vocal tracts of the Neanderthals resembled those of the apes -more significant issue - "vocal tracts ..were without language." "The vocal tracts of the Neanderthals" "the" still create the specificity and compare with specific apes.