Which of the following transactions takes place in factor markets?

A$.$ Justin receives $$30$ in exchange for mowing his neighbor's lawn.

B$.$ Jake purchases $1,000$ shares of stock in the Wal $-$ Mart Corporation through his online trading accour

C$.$ Lucille receives a $$500$ check from the U$.$S$.$ Social Security Administration.

D$.$ Sam enters the winning bid on a grand piano at a local auction.

E$.$ Henry receives a commission from his employer for selling a new automobile.