The vector a = α i +2 j + β k lies in the plane of the vectors b = i + j and c = i + k and bisects the angle between b and c. Then, which one of the following gives possible values of α and β?
(a) α =1, β = 1
(b) α =2, β = 2
(c) α =1, β = 2
(d) α =2, β = 1
