A. Sam's family adopted Max because...

1. The text states, "We adopted him from a shelter when he was just a small puppy with floppy ears and boundless energy." This implies they were looking for a companion.

2. The text also mentions, "Max is a loyal pet and loves me very much." and "He is not just a pet; he is a beloved member of our family." This reinforces the idea of wanting a loyal friend.

3. Option 4, "they wanted to have a loyal friend," best summarizes the family's motivation for adopting Max.