Consider the following C function definition.int fX(char *a) { char *b = a; while(*b) b++; return b - a; }Which of the following statements is/are TRUE?

The given function fX calculates the length of a null-terminated string (similar to strlen):

1. It initializes a pointer b to the start of the string a.

2. The loop while(*b) traverses the characters until it encounters the null-terminating character \0 (which evaluates to $0$ / false).

3. It returns the pointer difference b - a, which gives the integer length of the string.

Evaluating the statements:

• Option A: Passing a string literal "abcd" provides a pointer to a valid null-terminated character sequence ('a', 'b', 'c', 'd', '\0'). The function terminates and returns $4$. Hence, A is TRUE.

• Option B: An array declared as char c[] = "abcd" is null-terminated and decays to char * when passed to fX(c), returning $4$. Hence, B is TRUE.

• Option C: The syntax of the function is completely valid C code and will compile without errors. Hence, C is FALSE.

• Option D: A pointer initialized as char *c = "abcd" points to a valid null-terminated string literal, and passing it to fX(c) returns $4$. Hence, D is TRUE.

Thus, statements A, B, and D are TRUE.