Methanol can be gently oxidized with hot copper metal. What is(are) the product(s) of this oxidation?

$ \textbf{(A) }\text{Acetic acid}\qquad\textbf{(B) }\text{Carbon dioxide + Water}\qquad\textbf{(C) }\text{Ethanol} \qquad\textbf{(D) }\text{Methanal} \qquad$
1. Methanol ($\text{CH}_3\text{OH}$) is a primary alcohol.
2. When a primary alcohol is oxidized, it first forms an aldehyde. This is a well-known reaction in organic chemistry.
3. The oxidation of methanol involves the removal of two hydrogen atoms (one from the hydroxyl group and one from the carbon atom) to form methanal ($\text{HCHO}$), which is the simplest aldehyde.
4. The reaction can be represented as:
   \[
   \text{CH}_3\text{OH} + \text{[O]} \rightarrow \text{HCHO} + \text{H}_2\text{O}
   \]
   Here, $\text{[O]}$ represents an oxidizing agent.
5. Therefore, the product of the oxidation of methanol with hot copper metal is methanal.

The final answer is $\boxed{\text{Methanal}}$