No national productivity measures are available for underground industries that may exist but remain unreported. However, at least some industries that are run entirely by self employed industrialists are included in national productivity measures. From this information, which of the following can be validly concluded?

Introduction / Context:
This critical reasoning question involves drawing a logically valid conclusion from two factual statements. We are told how underground industries relate to national productivity measures and we are told that some industries run entirely by self employed industrialists are included in those measures. The goal is to identify the one conclusion that must be true on the basis of the given information, without adding extra assumptions.

Given Data / Assumptions:

• No national productivity measures are available for underground industries that remain unreported.
• Therefore, underground industries are not included in national productivity measures.
• At least some industries that are run entirely by self employed industrialists are included in national productivity measures.
• We must find a conclusion that follows with certainty from these premises.

Concept / Approach:
The key logical structure is about inclusion and exclusion from national productivity measures. The first statement tells us that if an industry is underground, then it is not measured. The second statement tells us that at least one industry run entirely by self employed industrialists is measured. From this, we can infer something about whether such industries are underground or not. The correct conclusion will follow directly from combining these two statements. Conclusions that speculate about all such industries, or about non self employed sectors, go beyond the information given.

Step-by-Step Solution:
Step 1: From the first statement, if an industry is underground, it does not appear in national productivity measures.Step 2: The contrapositive is that if an industry appears in national productivity measures, then it is not underground.Step 3: The second statement says that at least some industries run entirely by self employed industrialists are included in national productivity measures.Step 4: Applying the contrapositive, any industry that is included in national productivity measures cannot be an underground industry.Step 5: Therefore, at least some industries run entirely by self employed industrialists are not underground industries, because at least one such industry is measured.Step 6: This matches option D exactly.

Verification / Alternative check:

Why Other Options Are Wrong:

• Option A goes beyond the premises by asserting the existence of underground self employed industries.
• Option B incorrectly claims that none of the self employed industries are underground, which is stronger than what we can infer.
• Option C asserts the existence of other underground industries but the premises do not require any specific examples.
• Option E makes an absolute claim about all underground industries that is unsupported.

Common Pitfalls:

• Confusing what might be true with what must be true based on the premises.
• Misreading the structure of the first statement and failing to use the contrapositive.
• Assuming additional facts about underground industries or self employed industries that are not stated.

Final Answer:
The valid conclusion is that there are at least some industries run entirely by self employed industrialists that are not underground industries.