Answers:
Diameter - B)
Circumference - F)
Radius - C) or E)*
Secant - E) or C)*
Concentric circles - D)
Arc - A)
* Please, note that you described option C and option E with the same exact words. One of the two is supposed to be different.
Let's see the definition of each term of the list on the left in order to find the right description:
Diameter = any segment connecting two points on a circle passing through its center. Therefore, the correct description is B) a segment between two points on a circle that passes through its center.
Circumference = length of the distance around the circle (it's a sort of perimeter of the circle). Therefore, the correct description is F) the distance around a circle
Radius = constant distance from the center to any point on the circle. Therefore, the correct description is C/E) a line segment connecting the center C and a point B on the circle.
Secant = a line that intersects a circle at any two points. Therefore the correct description is E/C) Circle A and a line segment connecting the points B and C which are both on the circle.
Concentric circles = two circles positioned such as the center of the first one coincides with the center of the second one. Therefore the correct description is D) Two circles that share the same center.
Arc = part of the curve along the perimeter of a circle. Therefore, the correct description is A) a piece of the circumference of a circle.