With 1-4. urgent need on physics questions. 100% correct answers

1).  Speed of any wave = (wavelength) x (frequency) .  I got 4.5 m/s in my head, but you need to check this.

2).  and  3).  are marked correctly

4).  Transverse waves have crests and troughs.  But sound waves are longitudinal waves, so they don't have any.  The wavelength of a sound wave is the distance between consecutive centers of compression (or rarefaction).

correct it is c.) b b

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle