I think it's A) When we get home we could play video games because it answers a who? what? when? when? why? how? question and it contains a subject as well as a verb.
There are 12 months in a year.
My birthday is in 3 months.
In 6 months we finish school.
I don't like all months of the year.
The first three major parts in a business letter, in order, are the date you wrote the letter, the reference line and the inside address of the recipient.
