i got these two questions wrong

can you explain why?

Which is correct about malloc and free? Choose all that are applicable. If p is a pointer, free(p) sets p 's value to NULL Memory leak is acceptable because C has garbage collection Array indexes starts at zero One malloc must match one and only one free Which is correct about heap memory? Stores the return location of function call Must use pointers to access Allocated at run time First-in, First-out A frame is pushed when a function is called Must be freed by programs explicitly First-in, Last-out