153- The number of equivalence relations on the set $\{a,b,c,d\}$ that include $(a,b)$ is which of the following? $$3 \ (1) \hspace{2cm} 4 \ (2) \hspace{2cm} 5 \ (3) \hspace{2cm} 6 \ (4)$$
\textbf{153-} The number of equivalence relations on the set $\{a,b,c,d\}$ that include $(a,b)$ is which of the following?
$$3 \ (1) \hspace{2cm} 4 \ (2) \hspace{2cm} 5 \ (3) \hspace{2cm} 6 \ (4)$$
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