question: What is the definition of a weakly symmetric channel? option 1: The rows of the channel transition matrix are permutations of each other and the columns are permutations of each other. option 2: Every row of the transition matrix is a permutation of every other row and all the column sums are equal. option 3: All rows of the transition matrix have the same entries and all columns have the same entries. option 4: The rows and columns of the channel transition matrix have equal sums. option 5: Every row of the transition matrix is a permutation of every other row and all column sums are unequal. 