HELP ME OUT PLEASE!!

Barium sulfate, BaSO4 is a white crystalline solid that is insoluble in water. It is used by doctors to diagnose problems with the digestive system,

Barium hydroxide, Ba(OH)2 is also a white crystalline solid and is used in wastewater treatment.

How many more oxygen atoms are represented in the formula for barium sulfate than in the formula for barium hydroxide?

A) 2

B) 4

C) 1

D) 8​​