In English, there are many different phrases that have been developed mostly by Americans (in America), One of which is "I COULD care less". This is not a propper phrase (it used to be "i COULDENT care less") because it suggests that you still care and you could still have a little less care. WHY DO PEOPLE SAY I COULD CARE LESS!
i will give .

A number of linguists have suggested that the phrase "could care less" has a sarcastic connotation, implying something along the lines of "Ha!" As if there was anything in the world about which I couldn't care less.” Some American Yiddish-inflected phrases work in this way, such as "I should be so lucky!" (which means "there's no way I'll ever be that lucky") and "I should care!" (Why should I be concerned?) Even if "could care less" wasn't meant to be sarcastic, it fits in well enough with the other forms of the language to help it stick around.

The use of the phrase "could care less" can be traced back to 1955, with "couldn't care less" appearing only a decade earlier. But the phrase "no one could care less than I" had been around for a long time. Consider how you would react to such a phrase in a specific type of conversation. “I've never been insulted like this in my life!” They have no right to imply such a thing! No one is more unconcerned about the trappings of celebrity than I!”

Hope this helps and if it does, don't be afraid to give my answer a "Thanks" and maybe a Brainliest if it's correct?  

i feel like it is actually b.

3 is blunder, i’m not sure about the last one but the first two look correct