Answer
The maximum possible horizontal acceleration without slipping is (d) 1.2 g.
Work Step by Step
Since the runner is not slipping, we need to use the force of static friction. To find the maximum possible acceleration without slipping, we can assume that the force of static friction is at a maximum.
$F_f = ma$
$mg~\mu_s = ma$
$a = g~\mu_s = 1.2~g$
The maximum possible horizontal acceleration without slipping is (d) 1.2 g.
