"How to be bad" isn't an object, though. "Connaitre" is for acquaintance with a person, place, or thing. What he knows, in this case, is basically information: "In order to be bad, I must steal from babies, kick dogs, and grow a twirly moustache" (for example).
I got the multiple choice thing wrong because I didn't tick "Il sait comment être mechant".
Is "mechant" really a direct synonym for "bad"? Sure it's a negative word, but I always thought it was translated slightly differently as "fierce" or "nasty" that sort of thing.
Can sait /or connait be interchangeable in this sentence. I like, someone else on this forum, thought sait refers to things and connait to people. ?? Thank you
It has to be savoir here for the simple reason that connaître is only used with noun phrases. Je connais John, je connais ce librairie, je connais très bien New York, etc