. Plastic bags will cause pollution .. they are very hard to dissolve. A. so B. but C. or D. because

Plastic bags will cause pollution ____ they are very hard to dissolve.

Tạm dịch: Túi nilon sẽ gây ô nhiễm ___ chúng rất khó hòa tan.

Theo ngữ cảnh ⇒ Plastic bags will cause pollution because they are very hard to dissolve.