A man can rowa distance of 8 km downstream in a certain time and can row 6 km upstream in the same time. If he rows 24 km upstream and the same distance downstream in $$1\frac{2}{4}$$ hours, then the speed (in km/h) of the current is:

A

$$4\frac{1}{2}$$

B

$$4$$

C

$$3$$

D

$$2\frac{1}{2}$$