can someone give the explanation

[swethav12]

(man) Did you hear that my parents are planning a trip to Vancouver?
(woman) What for?
(narrator) What does the woman want to know?
a)what travel plans philip is making
b)how philip's parents are going to travel
c)what philip said
d)where philip heard the news

thanks in advance
swetha

[Ethelstan]

Wow, another short conversation tough question

Observation: This question is an inference question type. To infer means to accurately predicts from the conversation

In this conversation, simply, the woman is interested to know the purpose of Philip asking.

A - Obviously wrong. Its phillip's parent that are planning to travel not phillip
B - Obviously wrong. Phillip himself is (or seemed) uncertain, so he asked the woman, and its impossible for the woman to ask what is uncertain to him
D - The expression what for isn't intended to ask this question. This answer is somehow inaccurate

Based on the elimination method, the correct answer is C

C - Somehow accurate. The only option that has certain degree of accuracy compared to other option which completely inaccurate.