Got more complicated...

... not my fault...

So, seems (to me) that Minute wave ((a)) still needs one more motive wave downwards to get completed. Then, Minute wave ((b)) would follow, breaching the Minute wave ((a))'s channel.
And then, Minute wave ((c)) would unfold to complete the zigzag and hence Minor wave D of the Intermediate triangle wave (B).

Or not...