Matthew willingly allows anyone to hold him or change his diapers, but he seems to be especially happy in the arms of his mother, father, or regular day care provider. without knowing anything else about matthew, you might reasonably guess that he is:

two to six months old

Explanation:

By the months of age babies can already visually recognize the people who care for him (such as father, mother and day care). In addition to the smell and voice, the baby has one more feature to know when they are around. From two months to six months old, baby also begins to smile at everyone who approaches him smiling. He looks at people, babbles and makes prolonged vocalizations, actively participating in the home. For this reason, without knowing anything about Matthew, we can say that he is between 2 and 6 months old.