The importance of sensation according to Locke is A. <em>It is the means by which we acquire basic knowledge of the world around us.</em>
Locke emphasizes that our knowledge of the external world is not based on inference or reasoning, nor based on ideas that are already in our minds. It is based on sensation. That is to say that knowledge is acquired by means of the senses or sensory experience. Therefore perception is a key aspect of knowledge.
so, the first sentence informs you that it's raining cats and dogs. when you add the comma after raining, the meaning completely changes. the speaker is telling the cats and dogs that it is raining.
