Answer:
Q1: To turn over a new leaf [Railways, 1995]
Answer: A) To change completely one’s course of action.
Q2: A fair crack of the whip
Answer: B) A good luck check
Q3: To talk one’s head off
Answer: D) Talk excessively
Q4: To wrangle over a donkey's shadow [SBI PO 1984]
Answer: B) To quarrel over trifles