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1 . Consider a group of 8 people, consisting of Simon, John, and 6 other people. How many ways are there to arrange these 8 people on a horizontal line such that Simon and John are standing next to each other? (The order on the line matters and Simon is either to the left or to the right of John.)
(a)
$7 \cdot 6!$
(b)
$8 \cdot 6!$
(c)
$2 \cdot 8 \cdot 6!$
(d)
$2 \cdot 7 \cdot 6!$