[单选题]
The half-life of rad2fb1nv8n) -* vonxyaxbv n yu/cu8.e8ioactive iodine-137 is6r((*fg h 8bwlndg0 ys*ugp k/ 8.0 days. How many iodine nuclei are necessf/lgkg*hp 8uds( b n6( yg0wr*ary to produce an activity of $1.0 \; \mu Ci$?
A. $2.9 \times 10^{9}$
B. $4.6 \times 10^{9}$
C. $3.7 \times 10^{10}$
D. $7.6 \times 10^{12}$
