In a time-position graph where the velocity of an object is constant, the slope of the line represents the velocity of the object. If the object is in motion with a constant velocity, the slope will be a non-zero constant (either positive or negative depending on the direction of motion).
Based on the options provided, the correct response is:
None of the provided responses accurately describe a constant velocity situation.
However, if the velocity is constant and the line is neither horizontal nor vertical, the slope would either be positive or negative reflecting the object's constant motion. If the options were more accurate, one suitable response would be:
"The slope of the line is constant (either positive or negative) and the object will be in motion."
Since this is not offered directly, it seems there might be a misunderstanding in the provided options.