How Many Calcium,titanium,and Oxygen Ions Are There in the Perovskite

How many calcium,titanium,and oxygen ions are there in the perovskite unit cell shown below?

A) 1 Ca²⁺, 2 Ti⁴⁺, and 3 O^{2 -}
B) 1 Ca²⁺, 1 Ti⁴⁺, and 6 O^{2 -}
C) 1 Ca²⁺, 4 Ti⁴⁺, and 6 O^{2 -}
D) 1 Ca²⁺, 1 Ti⁴⁺, and 3 O^{2 -}
E) 1 Ca²⁺, 2 Ti⁴⁺, and 6 O^{2 -}