For each of the following transactions, indicate the two (or more) accounts that are affected and how they are affected (increase or decrease). Indicate whether the accounts are debited or credited.
a. Cash is invested by the stockholders.
b. Merchandise is purchased on account.
c. The merchandise is paid for.
d. Insurance is purchased and paid for.
e. Merchandise is sold on account.
f. Dividends are paid to the stockholders.