Answer
$4.4\times10^{3}\,Bq$
Work Step by Step
As $1\,Ci=3.7\times10^{10}\,Bq$ and the prefix nano (n) stands for $10^{-9}$, we have
$120\,nCi=120\,nCi\times\frac{10^{-9}}{nano}\times\frac{3.7\times10^{10}\,Bq}{1\,Ci}$
$=4.4\times10^{3}\,Bq$