A. 49

**B. 94 (Correct)**

C. 83

D. Either (a) or (b)

E. None of these

Explanation:

Let the number be in the form of 10a + b

Number formed by interchanging a and b = 10b + a.

a + b = 13 — (1)

10b + a = 10a + b – 45

45 = 9a – 9b => a – b = 5 — (2)

Adding (1) and (2), we get

2a = 18 => a = 9 and b = 4

The number is: 94.