Dr Rogan Calculates a Correlation Coefficient of -0

Dr. Rogan calculates a correlation coefficient of -0.98 between the amount of marijuana smoked and short-term memory capacity. From this correlation coefficient, Dr. Professor can conclude that:

A) smoking marijuana reduces short-term memory capacity.
B) low short-term memory capacity causes people to smoke more marijuana.
C) marijuana consumption and short-term memory capacity are negatively correlated.
D) there is no relationship between marijuana consumption and short-term memory.