A cistern 6 m long and 4 m wide contains water up to a depth of 1 m 25 cm. The total area of the west surface is :
Choose the correct choice from the following:
A) 49 m 2
B) 50 m 2
C) 53.5 m 2
D) 55 m 2
E) none of these

Rationale: "solution area of the west surface = [ 2 ( lb + bh + lh ) - lb ] = 2 ( bh + lh ) + lb = [ 2 ( 4 × 1.25 + 6 × 1.25 ) + 6 × 4 ] m 2 = 49 m 2 . answer a"
Answer: A