Everett, a 10-year-old boy with an IQ of 48, would be classified as:

The classification of intellectual disability is guided by specific IQ ranges. In this case, an IQ score of 48 falls within the range typically associated with moderate intellectual disability, which is classified as an IQ between 35 and 49. Therefore, the appropriate classification for Everett would be "moderately retarded," rather than mildly.

Mild intellectual disability usually corresponds to IQs ranging from about 50 to 70, which makes it clear that the answer indicating mildly retarded is not suitable for Everett's score. The terms "severely retarded" or "average intelligence" also do not fit, as severly retarded typically applies to those with IQs below 20 or 25, while average intelligence is usually characterized by a score around 100.

In summary, based on the standard criteria for classifying intellectual disabilities, a score of 48 indicates that Everett fits the classification of moderate intellectual disability.