A 952 * 10¯⁵ Mol Sample of Rubidium-86 Emits 8 $\beta$

A 9.52 * 10¯⁵ mol sample of rubidium-86 emits 8.87 * 10¹⁶ $\beta$ particles in one hour. What is the half-life of rubidium-86?

A) 2.23 *10¯³ h
B) 1.55 *10¯³ h
C) 448 h
D) 645 h
E) None of these choices is correct.