In each of the following groups

In each of the following groups of words, there are four underlined letters or letter combinations marked A, B, C and D. Compare the underlined parts and identify the one that is different from the others in pronunciation. Mark your answer by blackening the corresponding letter on the Answer Sheet.
A、ges[ture]
B、ma[ture]
C、mix[ture]
D、struc[ture]
【正确答案】：B