The rope shown at an instant is carrying a wave travelling towards right, created by a source vibrating at a frequency\[n\]. Consider the following statements I. The speed of the wave is \[4n\times ab\] II. The medium at \[a\] will be in the same phase as \[d\]after \[\frac{4}{3n}s\] III. The phase difference between \[b\] and \[e\] is \[\frac{3\pi }{2}\] Which of these statements are correct [AMU 2001]

• A.            I, II and III                              
• B.            II only                                      
• C.            I and III                                   
• D.            III only