At marriage, average age of husband and wife was 25 years, so total age was 50 years. Son was born 2 years after marriage. Present average age of all three is 24 years, so total present age is 72 years. Let t be years since marriage. Present ages: husband's age + wife's age + son's age = (50 - 2t for parents combined) + (t - 2) for son = 48 - t + t - 2 = 46. Wait, let me recalculate: if t years have passed since marriage, husband and wife are now (h + t) and (w + t), son is (t - 2). Total: h + w + 2t + t - 2 = 50 + 3t - 2 = 48 + 3t = 72. Therefore 3t = 24, so t = 8 years. Since 8 is not among options 6, 5, 9, or 4, option E (None of these) is correct.