We are asked to find the length of \( AB \), where points lie on a geometric figure involving a quarter circle (with center \( O \)), and three right angles are given at \( \angle YBC, \angle CAX, \angle YOX = 90^\circ \).
Statement I: Radius of the arc is given.
This gives us the total length \( OX \), but it does not tell us anything directly about where point \( B \) lies, or how triangle \( ABO \) is structured. So, not sufficient.
Statement II: \( OA = 5 \)
This gives one side, but again, without knowing the radius or coordinates of point \( B \), it is not enough to determine length \( AB \). Still not sufficient.
Combining both: Even with both, we know OA = 5 and radius = 5 (since arc is centered at O and touches X), but we do not have a complete triangle to determine AB without further positional information about B and C.
Hence, we cannot find the exact length of AB even with both statements.