The number of rooted binary trees with $n$ nodes is,

GATE · 1990 · CS · Question 3 subparts

1. A.

   Equal to the number of ways of multiplying $(n+1)$ matrices.

2. B.

   Equal to the number of ways of arranging $n$ out of $2 n$ distinct elements.

3. C.

   Equal to $\frac{1}{(n+1)}\binom{2n}{n}$.

4. D.

   Equal to $n!$.

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