Three rods made of the same material and having the same cross-section have been joined as shown in the figure. Each rod is of the same length. The left and right ends are kept at `0^@C` and `90^@C`, respectively. The temperature of junction of the three rods will be
(a) `45^@C` (b) `60^@C`
(c) `30^@C` (d) ` 20^@C`.
A. `45^(@)C`
B. `60^(@)C`
C. `30^(@)C`
D. `20^(@)C`
