Stem-changing -ir describe how you are feeling in the future and -ar & -er describe how you are feeling in the present.
A los ninos les gusta dibujar con muchos colores.
C. dibujar
English- The children like to draw with many colors.
Question:
Les dan Uds. Muchos regalos a sus amigos? Si, les (dan) muchos regalos
The missing word is "Dan"
Answer :Dan
Hope it helped