To determine the value of \( b \) given \( n = 48 \) and \( a = 60 \), we would need an equation or relationship involving \( a \), \( n \), and \( b \). Since you didn't provide a specific relationship or equation connecting these variables, it’s difficult to calculate \( b \).
However, if you are looking to find \( b \) based on common scenarios or patterns, please specify any mathematical relationships or context (like geometry, statistics, etc.) that might apply.
If there's a specific equation or context you're referring to, please provide that for a more accurate answer. Otherwise, if we are to choose from the options you've given, we cannot definitively calculate \( b \).