# A number n is chosen at random from $\{1,2,3,4.......,1000\}$. The probability that n is a number that leaves remainder 1 when divided by 7, is :

$\begin {array} {1 1} (a)\;\frac{71}{500} & \quad (b)\;\frac{143}{1000}\\ (c)\;\frac{72}{500} & \quad (d)\;\frac{71}{1000}\end {array}$

$(a)\;\frac{71}{500}$