Presidents often make with leaders of other nations because doing so does not require the approval of the senate.
a. informal treaties
b. presidential deals
c. recognition accords
d. executive agreements

The correct answer is: executive agreements. 

Executive agreements in general are agreements between the heads of state, and the president of United States can agree on them with other heads of state without the Senate's approval as long as it does not concern issues beyond the president's constitutional powers.