1. Which of the following rules is the divisibility rule of 4? a. The number is divisible by 4 if the digit at the unit place ends in 2,4,6,8 b. The number is divisible by 4 if the digit at the unit place ends in 0 or 5 c. The number is divisible by 4 if the last two digits is divisible by 4 d. The number is divisible by 4 if the last three digits is divisible by 4,​