Which of the following best describes a parametric equation?

Given x(t) = t^2 and y(t) = t^3, find dy/dx in terms of t.

Given x(t) = t^2, y(t) = t^3, find the equation of the tangent line at t = 1 in point-slope form.

Given x(t) = 2cos(t), y(t) = 2sin(t), find the arc length from t = 0 to t = π/2.

Given x(t) = t^3, y(t) = t^4, compute d^2y/dx^2 at t = 2.