From main() there are three function calling sequence
1) A1 -> A2
2) A2 -> A21 -> A1
These 1,2,3 are access links.
Now match with the given answer calling chains:
It shows a linear chain(only one function call from main()) which isn't correct and doesn't follow above sequence at all.
It is false because main() unable to call A1 directly.
It shows there is only two function call made by main(). That is not true and Frame pointer will also get updated by new A1 address block not will be old one.
main() has three function calling sequence present and Frame Pointer is holding the new A1 block address. That is true.