Answer:
0.808 M
Explanation:
Using Raoult's Law

where:
= vapor pressure of sea water( solution) = 23.09 mmHg
= vapor pressure of pure water (solute) = 23.76 mmHg
= mole fraction of water
∴






------ equation (1)
------ equation (2)
where;
number of moles of sea water
number of moles of pure water
equating above equation 1 and 2; we have :



NOW, Molarity = 



As we assume that the sea water contains only NaCl, if NaCl dissociates to Na⁺ and Cl⁻; we have 
Sorry if I'm wrong but I think that it is B.
D.
Misinterpretation of scientific knowledge for the influence of public opinion has been a repeating problem over the past, and usually creates a rift between the scientific community and the general public.