A Nuclear Explosion Produces Among a Lot of Other Things)

A nuclear explosion produces among a lot of other things) 7.9 × 10²³ Bq of iodine-131, which has a half-life of 8.05 d, and 5.7 × 10²¹ Bq of barium-140, which has a half-life of 12.8 d. The total decay rate that remains after 145 d is

A) 3.5 × 10¹⁸ Bq.
B) 1.16 × 10²⁰ Bq.
C) 2.2 × 10¹⁸ Bq.
D) 5.2 × 10¹⁸ Bq.
E) 7.3 × 10¹⁸ Bq.