A 2-dimensional parity check code is applied to (3x3 =) 9 information bits. Suppose that bit errors are independent and occur with probability p. Calculate the probability (in terms of p) that 4-bit errors are undetectable. Recall that a 4-bit error is undetectable if errors occur at the corners of a rectangle, as I showed in class. Remember that errors can occur in either the information bits or the parity bits