In a condenser of a power plant, the steam condenses at temperature of $$60^\circ$$ C. The cooling water enters at $$30^\circ$$C and leaves at $$45^\circ$$C. The logarithmic mean temperature difference will be around

A

$$20^\circ C$$

B

$$80^\circ C$$

C

$$200^\circ C$$

D

$$5^\circ C$$