( A ) $\overrightarrow{B} \; (x,t) = ( 9 \times 10^{-8} T) \hat{k}$
$ \sin [ 2 \pi (1.5 \times 10^{-6} x-2 \times 10^{14} t)]$
( B ) $\overrightarrow{B} \; (x,t) = ( 9 \times 10^{-8} T) \hat{j}$
$ \sin [ 1.5 \times 10^{-6} x-2 \times 10^{14} t)]$
( C ) $\overrightarrow{B} \; (x,t) = ( 9 \times 10^{-8} T) \hat{i}$
$ \sin [ 2 \pi (1.5 \times 10^{-8} x-2 \times 10^{14} t)]$
( D ) $\overrightarrow{B} \; (x,t) = ( 3 \times 10^{-8} T) \hat{j}$
$ \sin [ 2 \pi (1.5 \times 10^{-8} x-2 \times 10^{14} t)]$