A Beam of 10¹² Neutrons/second Is Incident on an Aluminum

A beam of 10¹² neutrons/second is incident on an aluminum foil of thickness 10^-4 m. The cross section for absorption is 0.23 bn. What is the reaction rate for neutrons being absorbed?

A) 1.4 × 10¹¹/s
B) 1.4 × 10⁹/s
C) 1.4 × 10⁸/s
D) 1.4 × 10¹⁰/s
E) 1.4 × 10¹²/s