Comenzar is an example of a .

e → ie stem-changing verb
e → i stem-changing verb
o → ue stem-changing verb
u→ ue stem-changing verb

It should be e->ie stem changing verb

It is letter b
los empleados se quejan de no tener un buen sueldo.

Pedro, josie, y heather fue a la quinceañera de virginia. the question is asking who went to the quinceañera. the person answering the question should answer using the ellos, ellas, and ustedes form if they were not part of that group of people.