Answer
There is not enough information to decide who is correct.
Work Step by Step
Clay:
$\underset{+2}{\underset\Rightarrow{2}}, \underset{+2}{\underset\Rightarrow{4}}, 6$, . . .
Ott:
$\underset{x2}{\underset\Rightarrow{2}}, \underset{x2}{\underset\Rightarrow{4}}, 8$, . . .
Stacie:
$\underset{+2}{\underset\Rightarrow{2}}, \underset{+3}{\underset\Rightarrow{4}}, 7$, . . .
