Correct option is (B) 5
Given the point \(A=(5 \cos \theta, 0)\) and \(B=(0,5 \sin \theta)\)
By distance formula,
The distance of \(A B =\sqrt{\left(x_{2}-x_{1}\right)^{2}+\left(y_{2}-y_{1}\right)^{2}}\)
\(=\sqrt{(0-5 \cos \theta)^{2}+(5 \sin \theta-0)^{2}}\)
\(=\sqrt{(-5 \cos \theta)^{2}+(5 \sin \theta)^{2}} \)
\(=\sqrt{25 \cos ^{2} \theta+25 \sin ^{2} \theta}\)
\(=\sqrt{25\left(\sin ^{2} \theta+\cos ^{2} \theta\right)}\)
\(=\sqrt{25 \times 1}\)
\(=5\)
