When positive integer d is divided by 6, the remainder is 1. Which of the following must be true?
I. d is a prime number
II. d is odd
III. d is divisible by 7 Choose the correct answer:	A) I only	B) II only	C) III only	D) I and II only	E) II and III only
d=6q+1   Examine II) put q=0,1,2,3....... we have d=1,7,13,...25 so d must be odd   Examine III) 14/6 has reminder 249/7 has reminder 1 so not always true   Examine I) d= 7 true but while 2 is prime, it does not give reminder 1   Answer: II only
<result>B</result>
When positive integer d is divided by 6, the remainder is 1. Which of the following must be true?
I. d is a prime number
II. d is odd
III. d is divisible by 7