If I’m not wrong I think it is len(classes). So ‘c’ would be 10 for mnist.
" c , automatically sets the last layer to have the correct number of activations because the data knows how many activations it needs."
I have had the same question but i don’t have an answer for that. From my understanding it should be c=2. (original vs generated images). Jeremy does delete that line form the code in th evideo but it is still present in the notebook.