Which of the following is the definition of CAS latency?

Which of the following is the definition of CAS latency?

A.
CAS latency is the ratio between the column access time and the clock cycle time.

B.
CAS latency is the ratio between the row access time and the clock cycle time.

C.
CAS latency is the ratio between the column access time and the data burst transfer time.

D.
CAS latency is the ratio between the row access time and the data burst transfer time.