Question 9

Statement 1 specifies that the set of bacteria $B$ is a subset of microorganisms $M$ ($B \subseteq M$). Statement 2 specifies that the set of pathogens $P$ is a subset of microorganisms $M$ ($P \subseteq M$).

Both $B$ and $P$ are subsets of $M$, but their mutual intersection $P \cap B$ is unconstrained. Either they overlap ($P \cap B \neq \emptyset$, meaning 'Some pathogens are bacteria'), or they are disjoint ($P \cap B = \emptyset$).

If Conclusion II ('All pathogens are not bacteria') is interpreted as 'No pathogens are bacteria' ($P \cap B = \emptyset$), then Conclusions I and II form an exhaustive complementary pair for non-empty $P$: either some pathogens are bacteria or none are, making 'Either conclusion I or II is correct' (option C).

If Conclusion II is evaluated as a standalone deductive certainty, neither conclusion necessarily follows from the premises alone. Because of this phrasing ambiguity, GATE officially accepted both option C and option D.