The correct substitutes would be " A. Ellos lo compraron
In English, Ellos compraron El Reloj Pulsera means : They (masculine) bought the watch
Reloj : Masculine singular Pronoun, which means that the objective pronoun should be : LO
Hope this helps
Technically, the black widow spider is the deadliest spider despite it's size, due to it's overwhelmingly potent venom, which can and will kill a human if no medical attention is sought out for the person bit.
You are likely to see a connotation used in both advertisement and also some university lectures. If only one answer is permitted, B is the best answer.
Find latitude and longitude