hey so I have been stuck on this question for the past few hours and I can't seem to figure it out. I am moving the pi bond one carbon/bond at a time but I can't seem to come up with the correct charges. I am probably making a really simple mistake but it's not clicking for me. I keep coming up with A but the correct answer is B. I am getting - for the nitrogen atom and + for the carbon atom and they are supposed to be opposite. I have attached a photo of the question im stuck on. Thanks!
U can't negative charge on N as then it would have to extend his octet which would high energy (do not have vacant d so will send excited electron in 3rd orbit)and hence will very higher energy than the structure drawn. Resonance structures must have similar. Let's just say N gives it's lone pair therefore double bond shift to carbon giving negative charge to it. In this structure octet is complete of N and not expanded .
The answer is III. Because, In this structure, all the atom have formal charge zero.