Final answer:
Meters (m) alone is not an appropriate unit for speed; the correct unit is meters per second (m/s). For velocity-time graphs, time is on the x-axis and velocity on the y-axis because time is the independent variable.
Step-by-step explanation:
The unit m, which stands for meters, is not an appropriate measurement unit for speed on its own because speed is a rate that measures distance per unit of time. To determine if m would be appropriate, we need the formula s = d/t, which implies that speed s is equal to distance d divided by time t. The unit of speed should therefore be distance divided by time, such as meters per second (m/s), not just meters.
When plotting velocity-time data on a graph, the common practice is to place time on the x-axis because it is the independent variable; the event's timing is controlled by the observer or the conditions of the experiment. Velocity, being the dependent variable, is placed on the y-axis since it depends on the time taken. Therefore, the correct answer is option c: Time would be on the x-axis and velocity on the y-axis, because time is a dependent variable and velocity is an independent variable.