\textbf{152-} In the directed graph below, the relation is $R$. The number of 1's in the adjacency matrix $M(ROR)$ is:
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\textit{[Figure: Directed graph with vertices a, b, c, d and directed edges between them]}
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(1) $7$ \hfill (2) $8$ \hfill (3) $9$ \hfill (4) $10$
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