To assess the reliability of the sentences, we must consider the basis of their claims, potential sources, and general knowledge about pioneer experiences:
A. The first pioneers to explore the opal fields found an unpleasant and unfriendly environment.
- This sentence seems reliable as it reflects the common challenges faced by pioneers in harsh environments.
B. None of the pioneers liked summer because it was dreadfully hot.
- This sentence might be seen as unreliable because it uses the word "none," which is an absolute statement and may not reflect the experiences of all pioneers.
C. To adapt to the challenging environment, pioneers built underground homes.
- This sentence is reliable as it aligns with historical practices in extreme climates, where building underground homes is a known strategy for adapting to harsh conditions.
Based on this analysis:
- A is reliable
- B is unreliable
- C is reliable
Therefore, the correct response would be: A is reliable, B is unreliable, C is reliable.