Central to the conflicts between israel and palestine is a dispute over a. gold b. oil c. land--> my answer d. how to dress neither jon nor corey had signed __ letter of intent. a. his b. their--> my answer are these correct?

1. The correct answer is C. land.
The central conflict between Israel and Palestine is over territory - Jerusalem, to be more precise. Both Israel and Palestine are claiming Jerusalem as their own, and neither country wants to concede. This is why there has been a war between these two countries since the mid-20th century. 

2. Neither Jon nor Corey had signed B. their letter of intent.
Given that there are two people involved (Jon and Corey), you cannot choose HIS because that is a singular pronoun (meaning that it would refer to one person only). The pronoun THEIR is plural, meaning that it would refer to more than one person, which is the case here.