[单选题]
If a material has an index k2*1,xmque6tb1,b+l yyswvk czu;a;psps6q2 xj(5sy .v x 6kkix*1vof refraction of 1.50, what is the speed of light through it?6; ;xpc skz xq(vs2xupjvi* a1y5ks6 .
A. $2.00 \times 10^{8} \; m/s$
B. $3.00 \times 10^{8} \; m/s$
C. $4.50 \times 10^{8} \; m/s$
D. $6.00 \times 10^{8} \; m/s$
