First National Bank made the following loans to Mr. James Wilson during the previous calendar year:
"¢ Loan A, made on February 2, is a loan for purchasing margin stock and is secured by margin stock
"¢ Loan B, made on March 15, is also for purchasing margin stock and is secured by margin stock
"¢ Loan C, made on June 30, is an unsecured loan for purchasing margin stock
"¢ Loan D, made on September 10, is for purchasing a car, secured by the car
All the loans are still outstanding at the end of the year. Which of the loans must be combined for purposes of the margin requirements of Regulation U?