Becquerel is the SI unit of radioactivity. One becquerel is defined as one kilo-becquerel (i.e. 103Bq ), while mega-becquerel is 106Bq and is written as MBq. It is equivalent to 1 -rutherford (rd). 1Bq=2.7×10−11C and1C=3.7×10Bq=37GBq Hence, (d) is the correct option.