Can you solve it under 1 minute ? Ochem concept question

During UV chlorination of methane, ethane appears with CH₃Cl, despite excess Cl₂ favoring further substitution. Considering radical consumption, chain interruption, and competing propagation steps, which step accounts for ethane formation while simultaneously reducing effective chain length?

A) Initiation (Cl–Cl homolysis)
B) Propagation (H abstraction)
C) Propagation (Cl₂ attack)
D) Termination (CH₃• + CH₃•)
E) Termination (Cl• + Cl•)