If both the pipes are opened, how many hours will be taken to fill the tank? I. The capacity of the tank is 400 litres. II. The pipe A fills the tank in 4 hours. III. The pipe B fills the tank in 6 hours.

• I. The capacity of the tank is 400 litres.
• II. The pipe A fills the tank in 4 hours.
• III. The pipe B fills the tank in 6 hours.
• A. Only I and II
• B. Only II and III
• C. All I, II and III
• D. Any two of the three
• E. Even with all the three statements, answer cannot be given.