Any cyclic parallelogram is a

Given a cyclic parallelogram.
In a cyclic quadrilateral, sum of measures of opposite angles is

180^{o}

.
The given cyclic quadrilateral is a parallelogram.
Hence, opposite pairs of angles will be congruent.

∠ 1 + ∠ 3 = 180^{o}

and

∠ 2 + ∠ 4 = 180^{o}

\Rightarrow 2 \times ∠ 1 = 180^{o}

and

2 \times ∠ 2 = 180^{o}

\Rightarrow ∠ 1 = ∠ 2 = 90^{o}

Hence,

∠ 3 = ∠ 4 = 90^{o}

Thus, the given parallelogram has all its angles equal to

90^{o}

i.e. a rectangle.
Hence, any cyclic parallelogram is a rectangle.
Therefore, option 1 is correct.

JEE