C语言Malloc and Strcpy，希望解决

这个应该怎么解决？要求是需要使用 malloc 和 free。照片第一张是原题，第二张是机翻。求忙帮编程一下，蟹蟹。上次那个人给我写的都是错的。

#include <stdio.h>
#include <stdlib.h>
 
char *copyString(char *str);
 
int main(int argc, char* argv[]) {
    // TODO BELOW
    //  part 2: need to check if "argc" is correct, and return appropriate message if not
    // TODO ABOVE
 
    char *argvCopy = copyString(argv[1]);
    printf("String 1: %s\n", argv[1]);
    printf("String 2: %s\n", argvCopy);
 
    // TODO BELOW
    //  part 3: some code here is missing! That will prevent memory leaks
    // TODO ABOVE
    return 0;
}
 
char *copyString(char *str) {
    // TODO BELOW
    //  part 1: need to use "malloc" to create new memory of the right size
    //  then use "strcpy" to copy data from string into your new array
    // TODO ABOVE
}

参考：

char *Ptr = NULL;

        Ptr = (char *)malloc(100 * sizeof(char));

        if (NULL == Ptr)
    {
        exit (1);
    }

        gets(Ptr);

        // code...

        free(Ptr);

        Ptr = NULL;