Consider the following phrase: Statement: A good man is hard to find…

Concept:

In Statement-and-Assumption reasoning, an assumption is implicit only if it is an unstated premise that the statement necessarily takes for granted. The test: negate the assumption — if the statement stops holding, the assumption is implicit; if the statement can still hold true, the assumption is not implicit. An implicit assumption must also be the minimal premise the statement requires, not a broader or more extreme claim than the statement warrants.

Application:

The statement says a good man is "hard to find" — a direct claim of scarcity. Applying the negation test to Assumption I: if it were false that there is very less chance of finding a man with good qualities, then a good man would NOT be hard to find, contradicting the statement. So Assumption I must be true for the statement to hold — it is implicit.

Applying the negation test to Assumption II: negate it — most men are NOT deceptive/snake-like. The statement can still be perfectly true under that negation, because a good man can be "hard to find" simply because good qualities are uncommon, without most men being deceptive or malicious. Assumption II reads a much stronger, unrelated claim about men's character into a statement that only comments on scarcity, so it is an unwarranted extrapolation, not something the statement requires.

Cross-check:

Since Assumption I passes the negation test and Assumption II does not, exactly one assumption — I — is implicit.

Why the other options don't fit:

• Only assumption II implicit — fails, since II is an extreme, unrequired claim about men's character, not a premise the scarcity statement depends on.

• Either I or II implicit — this pattern applies when two assumptions are mutually exclusive and exactly one of a complementary pair must hold; here the two assumptions are not a complementary pair, and I independently passes the negation test regardless of II.

• Neither I nor II implicit — fails, since assumption I clearly passes the negation test and is required by the statement.