Answer : Option D

Explanation :

Let Kiran's weight = x. Then
According to Kiran, 65 < x < 72 ------------(equation 1)
According to brother, 60 < x < 70 ------------(equation 2)
$MF#%\text{According to mother, }x \leq 68\text{ ------------(equation 3)}$MF#%
Given that equation 1,equation 2 and equation 3 are correct. By combining these equations,
we can write as
$MF#%65 < x \leq 68$MF#%
That is x = 66 or 67 or 68
$MF#%\text{average of different probable weights of Kiran = }\dfrac{66+67+68}{3} = 67$MF#%