Which of the following statements concatenates the contents of the $first variĀ¬
able, a space, and the contents of the $last variable, and then assigns the result to
the $name variable?
a. $name = $first . " " . $last;
b. $name = $first & " " & $last;
c. $name = $first + " " + $last;
d. $name = $first, " " , $last;