#help

Im confused on which logical indicator to use, which is where I ultimately made my mistake. In the explanation "only" is used which would result in /TW->P & /P->TW. However, why wasn't "cannot" used instead of "only" and when would you choose one over the other? I had used cannot which gave me TW->/P & P->/TW... resulting me selecting the wrong answer choice.

Unfortunately I wasn't able to attend. Will the recording be posted somewhere?