Economics- The largest part of the discretionary spending program is spent on ...

A. Humanities
B. Defense Spending
C. Educational
D. Health Care

B. Defense Spending

Explanation:

In government term, Discretionary spending refers to parts of government spending that is considered as 'optional' , and required the  appropriations of bill in order to be implemented.

Around 2/3 government of Government is considered as 'essential'. This amount cannot be allocated to the Discretionary spending since it accounted for social  programs that must be given to the citizens of Untied States.

The remaining 1/3 can be allocated to the Discretionary spending. From this portion, Defense spending took up the largest percentage (15% of the Discretionary spending). Defense spending  pay off our soldiers,  purchasing military's equipment's, investing in military's research/development, etc.

could you go a bit more in depth with you question? it's quite hard to understand. as soon as you do that i will be glad to : )

this is not a question