Why do we need to use the subjunctive tense for formal commands?

Choose the sentence that is grammatically correct. a. la comida es del senora b. la comida es de el senor c. la comida es del senor

How would you express the following question in english? : ¿cuántos libros hay? a. there are so many books. c. how many books are there? b. how much are the book? d. are the books many?

Tu hermano — en san francisco. a. vives ob. vivo o c. vive od. viven