Which of the following declarations define a structure named person which has three members: name, age and salary.

a$.$

struct $\{$

string name;

int age;

float salary;

$\}$ person;

b$.$

struct person

string name;

int age;

float salary;

c$.$

struct person $\{$

string name;

int age;

float salary;

$\}$;

d$.$

person $\{$

string name;

int age;

float salary;

$\}$;