Step 1: Use the distance formula
The distance between two points \( (x_1, y_1) \) and \( (x_2, y_2) \) is given by:
\[
d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}
\]
Step 2: Substitute values
Given points:
- \( (2\cos\theta, 0) \)
- \( (0, 2\sin\theta) \)
\[
d = \sqrt{(0 - 2\cos\theta)^2 + (2\sin\theta - 0)^2}
\]
\[
= \sqrt{(2\cos\theta)^2 + (2\sin\theta)^2}
\]
\[
= \sqrt{4\cos^2\theta + 4\sin^2\theta}
\]
\[
= \sqrt{4(\cos^2\theta + \sin^2\theta)}
\]
\[
= \sqrt{4(1)}
\]
\[
= \sqrt{4} = 2
\]
Thus, the correct answer is \( 2 \).