The average earning of all members of a family is 'k' Rs. per day. The difference between the 'highest' and the 'lowest' amount earned in the family is (k + 42) Rs. If the 'highest' and 'lowest' earning members are excluded the average earning of the group decreases by 2 Rs. If the minimum earning is more than 45 Rs. and is a multiple of '7' and the initial number of members in the family is equal to a 'prime' number, with 'both' of its digits also prime then which of the following will be the initial number of members in the family (where 'k' is the largest two-digit even number)