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.

Q: Question: Let f(x) = x^2 + bx + c. If f(1) = 0 and f(-8) = 0, then f(x) crosses the y-axis at what y-coordinate?

 Option A: -8

 Option B: -1

 Option C: 0

 Option D: 1

 Option E: 8

A: Option A
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Q: Question: The time taken by a man to row his boat upstream is twice the time taken by him to row the same distance downstream. If the speed of the boat in still water is 42 kmph, find the speed of the stream?

 Option A: 12

 Option B: 15

 Option C: 14

 Option D: 18

 Option E: 19

A: Option C
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Q: Question: A, B and C can do a piece of work in 24 days, 30 days and 40 days respectively. They began the work together but C left 4 days before the completion of the work. In how many days was the work completed?

 Option A: 32

 Option B: 88

 Option C: 67

 Option D: 11

 Option E: 66

A:
Option D
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