Answer:
(A) Nell's mom
Explanation:
It is given that Nell's mom makes chocolate milk with 30mL of chocolate syrup for every 2 ounces of milk.
⇒For 1 ounce of milk, she will make chocolate milk=

Also, it is given that Nell's dad adds 65mL of chocolate syrup for every 5 ounces of milk.
⇒For 1 ounce of milk, he will make chocolate milk=

Since, Nell's mom made 15mL of chocolate milk and his dad made 13mL of chocolate milk, thus Nell's mom made chocolate milk more chocolatey.
Hence, option A is correct.