Final answer:
The vector equation is r(t) = a + tb, and the parametric equations are x = at and y = bt.
Step-by-step explanation:
The question is asking for the vector equation and parametric equations of a line. The correct answer is D) The vector equation is given by r(t) = a + tb, and parametric equations are x = at, y = bt.
This means that the position vector of a point on the line is given by r(t) = a + tb, where a is the initial position vector and b is the direction vector of the line. The parametric equations x = at and y = bt represent the x-coordinate and y-coordinate of the point on the line as a function of the parameter t.