Final answer:
The phrase 'make the best of their own situation' indicates that the correct word to complete the sentence is 'best'. This implies using resilience to positively cope with challenges and achieve favorable outcomes.
Step-by-step explanation:
When a person has four strong walls in their life, they are said to be better able to be resilient, which is the ability to make the best of their own situation. The correct answer to fill in the blank is D. best. This metaphor suggests that having a strong support system (the four walls) can help someone cope effectively with life's challenges. Being resilient involves looking at the positives in a situation and working with what you have to achieve the most favorable outcome possible.