The Pakistan China border agreement was signed in

Pakistan signed a boundary agreement with China in 1963 which helped settle frontier issues in the Karakoram region. The accord provided a basis for cooperation and improved political relations between the two states at a time when regional alignments were shifting. This agreement later laid the groundwork for development projects like the Karakoram Highway and eventually CPEC. The year 1963 is recorded as the official signing date making option C the accurate answer for this historical event.