Is 说 in 听说 a resultative compliment?

The answer should be 见 or 到, which is a resultative compliment.

If you put the grammar terminology on aside, just look at the context itself, the answer should be 听见 or 听到。
the answer is already revealed in the sentence as there is the word 声音。 therefore, when it comes to sound, you can 听到 or 听见， it actually can be understood as the sound arrives or the sound appears.
In contrast, 听说，the 说 here means that gossip has been passing around. it means that word being said and you heard the words.

The answer should be 听到。First of all, 听说 indicated hear about or hear of sth said by somebody, so 说 is not a resultative compliment. Actually the phrasal verb '听说’ has a implicit the pronoun "whom", means 听 ** 说。On the other hand, '听到' is a phrase of verb-compliment structure which means you got voice or some information by your ears.