Answer:
Option a. is correct.
Explanation:
Given: Total amount with Tony is 60$. Pennants cost $7.50 and hats cost $11.99. 
To find: inequality that represents number of pennants bought by Tony if three of tony's grand kids want hats
Solution:
p denotes number of pennants and h denotes number of hats.
As three of tony's grand kids want hats, 

Total cost of 3 hats = 

Cost of one pennant = $7.50
According to question,

Also, being number of pennants, 

So, inequality that represents number of pennants Tony can buy is 

Option a. is correct.