Final answer:
The maxima of ceiling jet velocity and temperature in a steady-state fire situated near the center of a large room are typically about one-sixth to one-half the distance from the base of the fire to the ceiling, with one-half being a more common approximation.
Step-by-step explanation:
Ceiling jet refers to the relatively rapid gas flow in a shallow layer beneath the ceiling surface that is driven by the buoyancy of the hot combustion products from the plume. If the fire is burning at a steady state and if the centerline is near the center of a large room, the maxima of ceiling jet velocity and temperature exist at a distance below the ceiling equal to about one-sixth to one-half of the distance from the base of the fire to the ceiling.
This range can vary depending on various factors such as room geometry and fire size, but the common approximation used for safety and engineering assessments falls within this range. Therefore, of the options provided, both (A) One-quarter and (C) One-half could be considered correct depending on the specific circumstances, with (C) One-half being the more widely used approximation for a central plume in a large room assuming well-mixed conditions.