If abcd represents a positive four-digit number, where a, b, c and d are one-digit integers, which of the following CANNOT be true?  Choose the correct choice from the following answers:
A) a + b + c + d = 9  B) abcd = 9  C) a – b - c - d = 9  D) b – a - c - d = 9  E) a/b/c/d = 9
The (thousands place digit, a) cannot be zero, but (hundreds, tens and ones place digits; b, c and d) can be zero.   A is possible   B is possible   C is possible   b – a - c - d = 9 is NOT possible   E is possible   Answer: b – a - c - d = 9
<result>D</result>
If abcd represents a positive four-digit number, where a, b, c and d are one-digit integers, which of the following CANNOT be true?