<span>I recall this assignment your answer would be:
Jorge is mas serio que los otras chicas. Alicia es la mas mayor de todos. Lisa es mas baja que Alicia. Irene es mas baja que Jorge.</span>
the answer is: es. because carolina is singular
The answer is B. un libro.
Ella pide ayuda.
While ella pide translates to "she asks", and any of the other options might seem to make sense here, none of them actually do - ella pregunta is actually the correct form for the other options.
Hope this helps.