A sine wave described by the equation x=2sin(2πt−3x) is progressing along an x axis. In order that a standing wave is setup, what should be the equation of the reflected wave A. x=2sin(2πt−3x) B. x=2sin(2πt+3x) C. x=2sin(2πt−3x+π) D. x=2sin(2πt−3x+π/3)