Final answer:
The amount of the balance that is interest is $197,104.40.
Step-by-step explanation:
To find the amount of the balance that is interest, we need to subtract the initial deposit from the final balance. Hillary has been depositing $200 annually for 36 years, so her total deposits would be $200 x 36 = $7200.
Therefore, the amount of the balance that is interest is $421,304.40 - $7200 = $414,104.40. So, the answer is a) $197,104.40.