Consider the following statements regarding continental shelves 1. They have gentle slope and they extend up to 200m depth. 2. They are quite wide where mountains are close and parallel to the coast. 3. They are narrow where there are wide plains near the coast. 4. The widest continental is off the Arctic coast of Siberia.

• A. ?1 and 2 are true
• B. ?2 and 3 are true
• C. ?3 and 4 are true
• D. ?1 and 4 are true