What is the dark line lying in the middle of the $H$-zone called?

The muscles immune to fatigue are

In a $A$ state,the edge of thin filaments on either side of thick filaments $B$ overlap the free ends of $C$ filaments leaving the central part of thick filaments. This central part of thick filament,not overlapped by thin filaments is called $D$ zone.
Choose the correct options to fill the gaps $A, B, C$ and $D$,so as to complete the given $NCERT$ statement.

Muscle fatigue occurs due to the accumulation of . . . . . . .

Identify the incorrect statement regarding muscle contraction.

The neuromuscular junction or motor end plate is a junction between: