Question

is this correct please tell me sooner then later thank you

Answer 1

1. Correct. This is the distance around the circle, aka the perimeter.
2. False. Going from center (O) to the point A is the radius, which is half the diameter. Answer: radius
3. Correct. The diameter is a chord that goes through the center. A chord is any segment where the endpoints are on the circle's edge.
4. Correct. There are three radii shown in this diagram. The other radius is OC. Segment BC is a chord that is neither a diameter nor a radius.

In short, all you need to do is change "diameter" to "radius" in question 2. Other than that, you're perfect.