Let A vector `veca =alpha hati + 2hatj + beta hatk` `(alpha, beta in R)`,`veca` lies in the plane of the vectors, ` vecb= hati + hatj` and `vecc= hati -hatj+4hatk`. If `veca` bisects the angle between `vecb and vecc`, then :
A. `vec a* veci +3 =0`
B. `vec a*hati + 1=0`
C. `vec a * hatk+2=0`
D. `veca*hatk +4=0`