This is up to you and what your paper says, but the translation is:
We do a project in the English class.
It’ll be somos, meaning “are.” So the sentence will be Pedro, Juanita y yo SOMOS professores.
1. La papa y la zanahoria son verduras
2. La manzana y la fresa son frutas.
3. La limonada y el juego de naranja son refrescos
4. La torta y el helado son postres.
It is A, you are saying masculine because it is several people and when there are more than one it defaults to masculine. you dont however use plural again beacuse you will be referring to the dog. if there was more than one dog you would use C. But there is only one dog, so the correct answer is A