Definition: You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.
Input: Question: Compute the value of a + b + c + d.

 Option A: 40

 Option B: 50

 Option C: 60

 Option D: 70

 Option E: 80

Option D