The pictures were hard to see because they were blurry. Tonia decided to shoot a new roll of film.

What is the BEST way to combine the two sentences?
A.
The pictures were hard to see because, they were blurry, Tonia decided to shoot a new roll of film.
B.
The pictures were hard to see because they were blurry, so Tonia decided to shoot a new roll of film.
C.
The pictures were hard to see because they were blurry so Tonia decided to shoot a new roll of film.
D.
The pictures were hard to see, because they were blurry Tonia decided to shoot a new roll of film.