The Half-Life of Radioactive Iodine-137 Is $8.0$ Days How Many Iodine Nuclei Are Necessary to Produce an Iodine

The half-life of radioactive iodine-137 is $8.0$ days. How many iodine nuclei are necessary to produce an activity of $1.0 \mu \mathrm { Ci }$ ? $\left( 1 \mathrm { Ci } = 3.70 \times 10 ^ { 10 } \mathrm {~Bq} \right)$

A) $4.6 \times 10 ^ { 9 }$
B) $3.7 \times 10 ^ { 10 }$
C) $7.6 \times 10 ^ { 12 }$
D) $2.9 \times 10 ^ { 9 }$