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The number of tuples in the result of a left outer join operation will always be

(A) greater than the number of tuples in the result of the corresponding join operation.

(B)  at least equal to the number of tuples in the result of the corresponding join operation.

(C) less than the number of tuples in the result of the corresponding join operation.

(D) greater than the number of tuples in the result of the corresponding right outer join operation.
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The answer is option (B).

As when we perform left outer join, we may get more tuples present in corresponding relation. But if there are all matches w.r.t. the relations, then we get equal number of tuples as in left-relation.
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The answer is option (B).

When we perform left outer join, we may get more tuples then in corresponding join operation because Left outer join includes all tuples of normal join operation  + unmatched tuples of Left relation(null values in right relation attributes). So, Left outer join is at least equal to the number of tuples in the result of the corresponding join operation.