On the indicator card shown in the illustration, lines 'A' and 'B' indicate __________. Illustration MO-0108

Correct Answer: Option D — top dead center

In a standard diesel indicator diagram, the vertical line representing the peak pressure point at the end of the compression stroke corresponds to Top Dead Center (TDC). This is the point of minimum cylinder volume where the piston reverses direction, serving as the reference for ignition timing and combustion analysis.