Answer
(b) True. (d) True.
Work Step by Step
The normal vector to the $ yz $-plane is $\langle 1,0,0\rangle $ and using the fact that parallel planes have parallel normal vectors, we have:
(a) False, since $\langle 0,0,1\rangle $ is not parallel $\langle 1,0,0\rangle $.
(b) True.
(c) False, since $\langle 0,a,b\rangle $ is not parallel $\langle 1,0,0\rangle $.
(d) True, $ x=d $ has the normal vector $\langle 1,0,0\rangle $.
