Draw the products of the fragmentation that accounts for the cation at m/z 57 in the mass spectrum of 2-methylpentane.
a) CH₃⁺, C₂H₅⁺, C₄H₉⁺
b) CH₃⁺, C₂H₄⁺, C₃H₇⁺
c) C₂H₅⁺, C₃H₇⁺, C₄H₉⁺
d) C₂H₄⁺, C₃H₇⁺, C₄H₉⁺