Consider the following statements:

struct personalInfo

$\{$

string name;

int age;

float height;

float weight;

$\}$;

struct commonInfo

$\{$

string name;

int age;

$\}$;

personalInfo person$1,$ person$2$;

commonInfo person$3,$ person$4$;

Which of the following statements is valid in C$++?$

a$.$

person$2=$ person$1$;

b$.$

person$1=$ person$3$;

c$.$

person$2=$ person$3$;

d$.$

person$2=$ person$4$;