Question 2.

{But they don’t look like their cousins at all. Other molluscs include sea snails, sea slugs, bivalves - most are shelled invertebrates with a dorsal foot. Cephalopods are all arms, and can be as tiny as 1 centimetre and as large at 30 feet. Some of them have brains the size of a walnut, which is large for an invertebrate. . . .It makes sense for these molluscs to have added protection in the form of a higher cognition; they don’t have a shell covering them, and pretty much everything feeds on cephalopods, including humans.} 

We can understand that B, C and D are true - they are points of dissimilarities between octopuses and other molluscs [we are told that they have multiple appendages instead of a single dorsal foot and lack shells; they also have higher intelligence]. However, there is no information on whether humans consume molluscs like sea snails or not [furthermore, the author does not use this fact to claim that octopuses are distinct in this regard]. 

Hence, Option A is the correct choice.