which data type is 2.5?\nint\nstring\nsingle\nfloat

Brief Explanations:

In programming, an int is for integer values without a fractional part. A string is for text - like data. A single is a data type in some languages similar to float but with less precision in some cases. The number 2.5 has a fractional part and in most programming languages, floating - point data types are used to represent numbers with a fractional part. float is a common floating - point data type for such values.

Answer:

D. float