A character data type variable in any language is surrounded by '' and string data type variables are surrounded by "". This makes them different. String is collection of characters.
In option a, double is written for character which is wrong.
In option b, triple is written which is used nowhere.
in option d, open is written. A quote should always be closed for characters and strings.
The decimal data type is an exact numeric data type defined by its precision (total number of digits) and scale (number of digits to the right of the decimal point).
