Congress passed the marine mammal protection act in 1972 based on scientific data. what information could have been scientific justification for passing this act?

i'm stuck between --

a. scientists monitored an increase in marine mammal death rates in the world's oceans.

b. scientists monitored and observed the decline of marine mammal populations in the world's oceans.

Option B, Scientists monitored and observed the decline of marine mammal populations in the world's oceans.

Explanation:

The Marine Mammal Protection Act in 1972 was enacted with the motive of preserving the oceanic mammal species whose count has been reducing year on year. Thus, option B is correct

Option A cannot be correct as decrease in death rates of oceanic mammals will increase their population ultimately which in no case is a matter of concern due to which an act is required to bring in regulatory norms  for preserving any animal species.