ABC Inc Purchased Shares of DEF Inc as Follows

ABC Inc purchased shares of DEF Inc as follows:

June 30^th, 2013 4,000 shares @ $3 per share $12,000
June 30^th, 2014 3,000 shares @ $4 per share $12,000
June 30^th, 2015 3,000 shares @ $6 per share $18,000

The shares are considered to be passive investments. ABC Inc. has a December 31^st, year-end.
The market value of the DEF shares at each year-end was as follows:
December 31^st, 2013 $3.50 per share
December 31^st, 2014 $5.00 per share
December 31^st, 2015 $5.50 per share
On July 1^st, 2015, ABC sold half its shares in DEF Inc. for $6.50 per share.

-The total gain or loss realized on the sale of the shares was:

A) Nil
B) A $16,000 realized gain.
C) An $8,000 realized loss.
D) An $8,000 realized gain.