Beijing now boasts a large number of pet dogs there are more than $300$ shops for odd pet$-$care products.

Which of the following correctly use conjunctions and punctuation? Check all that apply.

Beijing now boasts a large number of pet dogs, so there are more than $300$ shops for odd pet$-$care products.

There are more than $300$ shops for odd pet$-$care products because Beijing now boasts a large number of pet dogs.

Since Beijing now boasts a large number of pet dogs, there are more than $300$ shops for odd pet$-$care products.

Beijing now boasts a large number of pet dogs, there are more than $300$ shops for odd pet$-$care products.