For both ir and er endings, if you want to conjugate a verb, remove the ir or er ending and add the ending that matches the subject and according to the tense. For instance, the imperfect tense that is used to talk about past actions, conditions, or events that occurred regularly or frequently or that were in progress in a moment in the past, takes the endings indicated in the Table below. So the conjugation differ in the root of the verb. For example:
The ending of the verb LEER is er and the ending of the verb VIVIR is ir. To conjugate these verbs for the second person singular (tú), remove the ending er and ir ending and add iste to the end of each word, therefore:
- Leías
- Vivías
So the ending is the same, but these two conjugations differs in the root of the word.
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
Ok, so first go to a Spanish app called Duolingo, trust me it will help a lot