题目

阅读理解 Posture Corrector For Men and Women●Let Our Posture Corrector Be Part of Your Pain-freeLife. As mybrother suffered clavicle (锁骨) pain aftera car accident, Dr. John advised us to try posture corrector. Luckily, mybrother came to his happiest self again. Besides correcting his posture, healso got relief from back, shoulder and neck pain all at the same time.●Good Posture Is Healthy For Both Men And Women. Wearingour back brace (背带) for sometime, you'll keep and hold back straight even without the posture corrector.Unlike regular posture correctors that are very hard and 函数f(x)=cos(3x-θ)-sin(3x-θ)是奇函数，则θ等于（    ） A.kπ(k∈Z)         B.kπ+ (k∈Z)       C.kπ+ (k∈Z)     D.kπ- (k∈Z)