The correct answer is option 'B': endanger all of them.

Explanation:

1. Sadao and Hana found a wounded soldier:
- Sadao and Hana, a Japanese couple, found a wounded American soldier on the beach near their house during World War II.
- They decided to take him in and hide him in their house.

2. The potential consequences of hiding the soldier:
- Hiding the wounded soldier in their house would put all of them in danger.
- The soldiers in the area were searching for the wounded soldier, and if they were to find out that Sadao and Hana were hiding him, they would be considered traitors and could face severe consequences.

3. Fear of police suspicion:
- Sadao and Hana were well aware that harboring the enemy soldier would arouse suspicion from the police and the authorities.
- They knew that if they were caught, it would not only bring trouble upon themselves but also their family and servants.

4. The risk to their safety:
- By keeping the wounded soldier in their house, Sadao and Hana were risking their own safety as well as the safety of their family.
- If the authorities were to find out about the hidden soldier, they could face imprisonment, torture, or even death.

5. The importance of secrecy:
- Sadao and Hana understood the need for secrecy to protect themselves and the wounded soldier.
- They took great precautions to ensure that no one discovered their secret, such as keeping the soldier hidden in a hidden room and avoiding any suspicious behavior.

Conclusion:
Hence, Sadao and Hana believed that keeping the wounded soldier in their house would endanger all of them. They were aware of the potential risks, including police suspicion and the severe consequences they could face if caught. Their decision to hide the soldier was driven by compassion but also carried significant risks to their own safety and the well-being of their family.