A.I. Explanation:

Option 1: "vast"

Explanation: While 'vast' suggests a large extent, it does not convey the emotional weight of the impact on the family as effectively as 'enormous.' The text emphasizes the significant emotional and physical toll on April and their sons, which is better captured by 'enormous.'

Option 2: "huge"

Explanation: The term 'huge' implies size but lacks the depth of meaning needed in this context. It does not fully express the profound emotional impact described in the text, making 'enormous' a more suitable choice.

Option 3: "giant"

Explanation: 'Giant' is similar to 'huge' in that it denotes size but fails to encapsulate the emotional significance of the impact on the family. The text requires a term that conveys a deeper sense of magnitude, which 'enormous' provides.

Option 4: "enormous"

Explanation: The word 'enormous' effectively captures the significant emotional and physical impact on April and their two sons. It aligns with the context of the text, which discusses the extensive injuries and their profound effects on the family, making it the most appropriate choice.