Consider the following Scala code: object Question { def f (x:Int) : () -> Int - { var c = x () => { C - c + x When this code is compiled with scalac, the closure built for the anonymous function is represented using a class. Which of the following best describes the fields that are required in that class? (Hint: recall that parameters in scala are immutable.) O private final scala.runtime.IntRef x$1; private final int x$1; private final scala.runtime.IntRef c$1; private final int x$1; private final int c$1; private final scala.runtime.IntRef x$1; private final scala.runtime.IntRef c$1; O private final int cPlusx$1;