Step 1: Rule.
Present continuous ("are driving") changes to past continuous ("was driving") in indirect speech.
Step 2: Check options.
(A) Wrong — tense not changed.
(B) Correct — "told… that he was driving fast."
(C) Wrong — introduces wrong verb "scolded."
(D) Wrong — incorrect modal "can say."
Step 3: Conclusion.
Answer is (B).