a) function concatenate()
{
return String.prototype.concat(”, arguments);
}
b) function concatenate()
{
return String.prototype.apply(”, arguments);
}
c) function concatenate()
{
return String.concat.apply(”, arguments);
}
d) function concatenate()
{
return String.prototype.concat.apply(”, arguments);
}

Answer: d
Explanation: The concat() method is used to merge two or more arrays. This method does not change the existing arrays, but instead returns a new array. apply takes an array of arguments and treats each element of that array as a single argument.