This is important for an exam tommorow.Pls answer

Which option completes the phrase below to make a grammatically correct sentence?


Samita was walking down the street, __________


A. when she saw a peculiar looking man limping across.


B. but she saw a peculiar looking man limping across.


C. because she saw a peculiar looking man limping across.


D. while she saw a peculiar looking man limping across.