Which type of oil pressure gauge indicates the pressure using direct pressure on the gauge?

The mechanical oil pressure gauge operates based on direct pressure, which makes it the correct answer in this instance. This type of gauge includes a physical tube connected to the engine's oil pressure system. As oil pressure builds up within the engine, it travels through this tube and exerts direct pressure on the gauge's internal mechanism, causing the needle to move and indicate the oil pressure level.

In contrast, electrical gauges use an electronic sensor to measure oil pressure, which then sends a signal to the gauge to display the reading. Digital gauges transform this information into a digital format for display but still rely on electronic sensors rather than direct pressure. Analog gauges, while they may show a needle like mechanical ones, can be either electrical or mechanical; however, the defining feature of a mechanical gauge is that it specifically uses direct oil pressure to provide a reading, clarifying why this choice is appropriate.