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.
#8: gritara #9:explicaba #10:cocinaba
1. True || 2. True || 3.True || 4.True || 5. False
Preterite is past tense..
tu quisite ir al parque. marcos me dio un regalo. mi padr3 me dio un sombrero de mexico.