It’s 4 because there’s a fanboy there
Composition almost always ends on a tonic chord.
There is no following to your question so I'm not sure how I can answer it!
1.How long have I known Bob
2.How long have Sue and Alan been married?
3.How long has George been unemployed?
4.How long have those books been here?
5.How long has Mary been at the airport?
6.How long has my sister been ill?
7.How long has she had a bad cold?
8.How long is Jan's hair?
9.How long have I had a yacht?
10.How long have they been in the restaurant?
11. How long have my parents been in London?
12.How long has the cat been under the table.
Hope this Helps:)!
I think it is a because you need to pause after line
