Identify correct statements about Myrdal's model:  

A. He gave the theory of cumulative causation.

B. Some growth centres grow faster and work as suction pumps.

C. The spread of development to the surrounding region around the growth centre is called backwash effect.

D. Pulling of all the dynamic elements to the growth center from the surrounding locations is called take-off stage.

Choose the correct answer from the options given below: