I the digit in the unit’s place of a two digit number is halved and the digit in ten’s place is doubled the number thus obtained is equal to the number obtained by interchanging the digits. Which of the following definitely true? a. Sum of the digits is as two digit number. b. Digit in the unit’s place is half of the digit in the tens place. c. Digit in the unit’s place and the ten’s place are equal. d. Digit in the units’ place is twice the digit in the ten’s place.