The two points being intersected by the line is not on the circle however, the line still intersects two points and it passes through the circle. That clearly shows a secant line.
AC is the diameter. (It's the line that divides the circle in half) GH is a chord. (It is just a part of a secant. It connects two points on the circle.) DE is a line segment. (It's a part of tangent line since it lies outside the circle)
Let us identify each points. AC is the diameter. GH is a chord. DE is a line segment.
So the secant here is B. EF
Secant is defined as: The two points being intersected by the line is not on the circle however, the line still intersects two points and it passes through the circle.