Answer:
A. Debit retained earnings for $18 million.
Explanation:
Before recording the journal entry, first we have to determine the dividend shares which are shown below:
= Number of shares × par value of share × common stock dividend percentage
= 30 million shares × $1 × 1%
= 0.30 million shares
Now the journal entry would be
Retained earnings Dr $18 million    (0.30 million shares × $60)
  To Common Stock $0.30 million    (0.30 million shares × $1
  To  Additional Paid-in Capital in excess of par - Common Stock $17.7 million
(Being the dividend is declared and the remaining balance is credited to the additional paid-in capital account)