Which of the following function is not avallable for all STL (Standard Template Lbrary) containers? O int size0 O void pop. back O void dlearo O bool empty D Question 18 5 pts Which of the following describes void push _back (const Object &x) under STL (Standard Template Library) in C++? O The element x is added to the end of the list O The element x is added to the front of the list O The clement x is added to the center of the list O Nonc of the above Question 19 5 pts Which of the following function is not available for vector container under STL (Standard Template Library) in C++ O int sizet) void push back(const Otpect 0 Yold push frontconst Object const Object & back) earch