Please answer these data structure questions

12. If a stack is used by an algorithm to check for balanced braces, which of the following is true once the end of the atring ia reached? a) the stack is empty b) the stack has one c) the stack has one d the stack has one and one - 13. What is Abstract Data Type (ADT)? Deacribe the definition of ADT. 14. What is the output of the following program? # include using namespace std; int main()