7. (10 points) Consider the following Java-like program that uses static scoping. void fun() { int a, b, c; /* definition 1 */ ... while (...) { int a, c, d; /* definition 2 */ ... < 1 while (...) { int d, e, f; /* definition 3 */ ... < 2 } ... < 3 } ... < 4 } For each of the four statements labeled 1-4 in this function, list all visible variables along with the definition statements (1-3) that define them.