Let the universe be “all people.” Define predicates:
$F(x)$: “$x$ is a Fields medalist$.$”
$M(x)$: “$x$ has won an International Mathematics Olympiad medal$.$”
$P(x)$: “$x$ is a poet$.$”
$D(x)$: “$x$ has dropped out of college$.$”
Let $j$ denote June Huh. From the passage we have the facts:
1) $F(j)$ (June Huh is a Fields medalist.)
2) $\neg M(j)$ (He did not win any IMO medals.)
3) $D(j)$ (He dropped out of college.)
4) $P(j)$ (He was also a poet.)
Now evaluate each option using these facts alone.
Option (A): “Every Fields medalist has won an IMO medal.”
Formal form: $\forall x\,\big(F(x)⇒ M(x)\big)$.
A single counterexample falsifies a universal statement. We know $F(j)$ and $\neg M(j)$, hence $j$ is a counterexample.
Therefore (A) is False.
Option (B): “Everyone who has dropped out of college has won the Fields medal.”
Formal form: $\forall x\,\big(D(x)⇒ F(x)\big)$.
From the passage we only know $D(j)$ and $F(j)$ for one person. This does not justify a universal rule about all dropouts.
Construct a model consistent with the passage but making (B) false: add a person $u$ with $D(u)$ and $\neg F(u)$. None of the given facts mention $u$, so the passage remains true while (B) fails.
Hence (B) cannot be inferred; it is Not entailed.
Option (C): “All Fields medalists are part-time poets.”
Formal form: $\forall x\,\big(F(x)⇒ P(x)\big)$.
Again, one instance $F(j)\wedge P(j)$ is insufficient to conclude a universal rule. We can conceive a person $v$ with $F(v)$ and $\neg P(v)$ without contradicting any given fact.
Therefore (C) is Not entailed.
Option (D): “Some Fields medalists have dropped out of college.”
Formal form: $\exists x\,\big(F(x)\wedge D(x)\big)$.
This is an existential statement and is directly witnessed by $x=j$ since $F(j)$ and $D(j)$ are both true. No additional assumptions are needed.
Therefore (D) is Certainly True.
Key logical lesson:
- Universal claims ($\forall$) require evidence about all members; a single counterexample suffices to refute them.
- Existential claims ($\exists$) require evidence about at least one member; a single confirmed instance proves them.
- The passage gives one concrete instance (June Huh) with properties $F$, $D$, $\neg M$, $P$. Thus only the existential statement in (D) is logically forced by the data.
\[
\boxed{\text{(D) Some Fields medalists have dropped out of college.}}
\]