The correct option is
B αA+αBWe will check all the options one by one.
Option A: →α(A+B)
αA+αB.
Clearly, option A is correct.
Option B: →α2A+α2B
=α2(A+B)≠α(A+B), unless and until α=α2.
∴ Option B is incorrect.
Option C:→√αA+√αB
√α(A+B)≠α(A+B), unless and until √α=α.
∴ Option C is incorrect.