In the function vpa('981',10), why do we put 981 within inverted commas?

• A. We can choose to not put the value within a pair of single inverted comma
• B. We do it so that we don't get an approximated value
• C. We do it to get the exact value as MATLAB computes exact values, of numerical expressions, when declared within a string
• D. We do it to get a floating-point approximated value, approximated to 14 digits