Presence of Bromine Produces M⁺

Presence of bromine produces M^{+ .} and (M+2) ^{+ .} peaks of equal intensity on a mass spectrum because:

A) . ⁸¹Br isotope has higher natural abundance than ⁷⁹Br isotope
B) . ⁷⁹Br and ⁸¹Br isotopes have almost equal natural abundance
C) . ⁷⁹Br isotope has higher natural abundance than ⁸¹Br isotope
D) none of these