350. The indicator card shown in the illustration is produced with a/an __________

The indicator card's trace, characterized by distinct pressure peaks separated by a baseline, is produced by a rotating drum indicator. This design continuously rotates the drum, creating an open record of pressure versus crank angle, unlike oscillating drum indicators which produce closed loops. The other options—balanced-diaphragm indicator, sliding camshaft, and oscillating drum—do not account for the card's specific shape or function.