2 pts Question 14 Which of the following is true about "Yellowbacks"? Choose the best answer. a. They were issued by some National Banks in California b. They were backed by Treasury Bonds but could also be redeemed for gold at those issuing banks O c. There were issued by some National Banks throughout the Northern states and territories O d. Since the National Banks issuing Yellowbacks would redeem them with gold they did not have to be backed by Treasury Bonds Oe. Both a and b are true f. Both a and d are true