$3$ points

Select all the correct answers. In C$++,$ array indices must be

None of these is correct

of integer $($int$)$ type. Array indices cannot be defined by decimal numbers $($floating point numbers$)$ like $2\mathrm{.}4$

Less than or equal to the declared size of the array

Non$-$negative integers $($that is to say, zero or positive integers$)$