Select the best answer for the question.

$12.$ RS$-232$ contains two data pins: Pin $2$ transmits data and Pin $3$ receives data. However, it isn't easy to define which pin is receiving and which pin is transmitting since the computers are sharing data. What tool can help fix this predicament?

A$.$ Null modem cable

B$.$ Data set ready $($DSR$)$ pin

C$.$ DB$-25$ connector

D$.$ Handshaking pins