The following program is to be tested for statement coverage: begin if (a = = b) {S1; exit;} else if (c = = d) {S2;} else {S3; exit;} S4; end The test cases T1, T2, T3 and T4 given below are expressed in terms of the properties satisfied by the values of variables a, b, c and d. The exact values are not given. T1 : a, b, c and d are all equal T2 : a, b, c and d are all distinct T3 : a=b and c !=d T4 : a !=b and c=d

Which of the test suites given below ensures coverage of statements S1, S2, S3 and S4?