The question asks which molecules are unstable at room temperature, but the molecular structures/options for A, B, C, and D are missing from the prompt.

Without the actual compounds, it is impossible to determine stability.

Step 1: What is required

To judge whether a molecule is unstable at room temperature, we must inspect its structure for features such as:

1. excessive ring strain,
2. cumulated double bonds in unsuitable systems,
3. antiaromaticity,
4. unstable functional group combinations,
5. highly reactive small-ring alkynes/alkenes, etc.

Step 2: Why the answer cannot be derived

Here, options are shown as:

• A:
• B:
• C:
• D:

but no structures/names are provided. Therefore, there is no chemical information to analyze.

Step 3: Comparison with stored answer

The stored correct answer is given as $B, C$, but since the options themselves are absent, I cannot independently verify that result from the question data.

Hence, I must disagree on verification grounds: the problem statement is incomplete.