Final answer:
The largest integer whose square root is an irrational number between 3 and 4 does not exist.
Step-by-step explanation:
The largest integer whose square root is an irrational number between 3 and 4 can be found by finding the largest perfect square less than 4 and taking its square root. In this case, the largest perfect square less than 4 is 3^2 = 9. Taking the square root of 9 gives a rational number, which is not between 3 and 4. Therefore, there is no integer whose square root is an irrational number between 3 and 4. Therefore, the correct answer is none of the given options (a) 12, (b) 15, (c) 16, or (d) 20.