15. Given four statements below determine which statement combination is correct 1. If a variable is declared as an extern in one file ther the variable is 2. A global variable that is declared in a file as a static (e.g., static 3. A static variable in a block of code car appear only once in a program a global variable int numCourses) is only visible to the functions in the file pg. 5 4. A block of code can have only one static variable A. statement 1 is true and s B. Statement 2 is true and statement 4 is not true C. Statement 2 is true and statement 1 is not true D. statement 3 is true and statement 3 is not txue E. None of the above tatement 3 is true