Answer: C

gmat_perfect wrote:Japanese researchers are producing a series of robots that can identify human facial expressions, to which they will then respond; their goal is primarily creating a robot that will empathize with us.

(A) expressions, to which they will then respond; their goal is primarily creating
(B) expressions, then responding to them; primarily to create
(C) expressions and then respond to them; the researchers' primary goal is to create
(D) expressions as well as giving a response to them; their primary goal is creation of
(E) expressions and responding to them; primarily, the researchers' goal is creating

OA: Later

"their": pronoun ambiguity

C rightly resolves it ! . Pick C.

C also introduces the adjective "primary" that modifies the noun "goal".

I picked C as well. Only because it was parallel and looked the best.

I have a question here:

Doesn't them (then respond to them) in Option C also represent pronoun ambiguity. them here can refer to emotions as well as the researchers can't it? Is pronoun ambiguity an absolute rule? Can someone shed light on this?

Pronoun ambiguity is not an absolute rule.

Also in C :

expressions : object

responding to THEM : object

so them is referring to expressions.

RumpelThickSkin wrote:I picked C as well. Only because it was parallel and looked the best.

I have a question here:

Doesn't them (then respond to them) in Option C also represent pronoun ambiguity. them here can refer to emotions as well as the researchers can't it? Is pronoun ambiguity an absolute rule? Can someone shed light on this?

If you declare Pronoun Ambiguity error whenever a pronoun is used after several nouns that it could technically refer to, you may find that the GMAT isn't as sensitive as you are (I've had that problem with ambiguity).

Ambiguity is a meaning issue; Only declare Pronoun Ambiguity when the ambiguity is so blatant as to distract from the meaning of the sentence. For example: "The girl and her mother arrived together, but she left alone."

If the meaning can be very easily determined, don't use Ambiguity to eliminate that answer unless you've done as much else as you can and you're still stuck between choices.

Good luck RumpelThickSkin
-Patrick