Preparing Entries for Treasury Stock Transactions

Charter Inc. has $600,000$ shares of $$1$ par common stock outstanding at the beginning of the year. Prepare entries for the following

transactions affecting stockholders' equity. Assume Paid$-$In Capital$-$Treasury Stock has a zero beginning balance.

a$.$ Jan. $31$: Purchased common stock as treasury shares, $1,200$ shares at $$15$ per share.

b$.$ Sep. $15$: Sold common treasury stock, $200$ shares at $$17$ per share.

c$.$ Dec. $20$: Sold common treasury stock, $250$ shares at $$13$ per share.