This question is about Pakistan's foreign trade policy in the mid-2000s, and the safest approach is to match each option against what is actually documented for that period.
China stands out clearly because the FTA with Pakistan was a specific, named agreement (unlike the looser preferential arrangements with the EU) and it explicitly included the five-year investment package mentioned in the question.
Let's summarize:
So the correct partner country is China, option (C).
Under which policy of expansion was the place marked in the map annexed by the British? 