Question

4. Complete the following sentence:

En la clase hay una ventana, una puerta y un
O escritorios
O reloj
O tarea
O puerta

Answer 1

The answer is B. None of the other words correlate with the word “un”

Answer 2

I believe that it would be B (reloj) since it is talking about how there is a window, a door and then a clock in a classroom.
It is also giving you the masculine singular form indicating that it can only be reloj.