In the context of a time-position graph where the velocity of an object is constant, the answer will be:
The slope of the line is equal to zero and the object will be stationary.
This implies that if the line is horizontal (zero slope), the object does not change its position over time, indicating that it is stationary.
However, if the velocity is constant and not zero, you would see a non-horizontal line (where the slope is positive or negative depending on direction), indicating the object is in motion, which isn't reflected in any of the options you've provided.
So, if the object is stationary, you're looking for "The slope of the line is equal to zero and the object will be stationary." If the object is in motion, you'd be looking for a non-zero slope line.