Analyze Statement I: "$CeO_2$ can be used for oxidation of aldehydes and ketones."

• Cerium commonly shows oxidation states $+3$ and $+4$.
• In $CeO_2$, cerium is in the $+4$ oxidation state.
• $Ce^{4+}$ is a good oxidizing agent, and cerium(IV) oxide is used in oxidation reactions in organic chemistry.
• Hence, $CeO_2$ can act as an oxidizing agent for suitable organic compounds, including aldehydes and ketones.

Therefore, Statement I is true.

Analyze Statement II: "Aqueous solution of $EuSO_4$ is a strong reducing agent."

• In $EuSO_4$, europium is in the $+2$ oxidation state because sulfate is $SO_4^{2-}$.
• Europium commonly exists in $+2$ and $+3$ states.
• The $Eu^{2+}$ ion readily gets oxidized to the more stable $Eu^{3+}$ state in aqueous solution.
• Therefore, $Eu^{2+}$ acts as a strong reducing agent.

Hence, aqueous $EuSO_4$ is a strong reducing agent, so Statement II is true.

Conclusion:

• Statement I: True
• Statement II: True

So the correct option is:

$\boxed{\text{D: Both Statement I and Statement II are true}}$

Comparison with stored correct answer:

• Derived answer: $D$
• Stored correct answer: $D$
• They match.