Read the following sentences:
I always get the vaccine. I haven’t gotten the flu in years.
Which revision below is a complex sentence?
The reason why I haven’t gotten the flu in years is because I always get the vaccine.
I always get the vaccine, so I haven’t gotten the flu in years.
I always get the vaccine, which means I haven’t gotten the flu in years.
I always get the vaccine; thus, I haven’t gotten the flu in years.