Answer:
D. This is a violation of position limits.
Step-by-step explanation:
John is managing 25 accounts, and when there is common control all accounts involved are aggregated to see if they are violating position limits.
John is buying 30,000 calls each for 10 of his accounts (30,000*10= 300,000) out of 25 accounts that he has discretionary options for.
ABCD corporation has position limit of 250,000 contracts on each side of the market.
So John is in violation of position limits. He bought 300,000 calls and ABCD corporation's limit is 250,000.