A transverse harmonic wave on a string is described by
                   yx,t=3.0sin36t+0.018x+π4
where x and y are in cm and t is in sec. The positive direction of x is from left to right.

(a) The wave is travelling from right to left.

(b) The speed of the wave is 20 m/s.

(c) The frequency of the wave is 5.7 Hz.

(d) The least distance between two successive crests in the wave is 2.5 cm.

Choose the correct alternatives:

1. (a, b, d)

2. (a, b, c)

3. (b, c, d)

4. (a, c, d)