How do you allocate a matrix using a single pointer in C?(r and c are the number of rows and columns respectively)

int *arr = (int *)malloc(r + c * sizeof(int));

int *arr = malloc(r * c * sizeof(int));

int *arr = (int *)malloc(r * c * sizeof(int));

int *arr = (int *)malloc(r * c * sizeof(arr));

How do you allocate a matrix using a single pointer in C?(r and c ar

1.	How do you allocate a matrix using a single pointer in C?(r and c are the number of rows and columns respectively)
A.	int arr = malloc(r c * sizeof(int));
B.	int arr = (int )malloc(r * c * sizeof(int));
C.	int arr = (int )malloc(r + c * sizeof(int));
D.	int arr = (int )malloc(r * c * sizeof(arr));
Answer» C. int arr = (int )malloc(r + c * sizeof(int));