Answer:
A
Explanation:
| x-6| = 15 , check if this is true for the given x values
for x= -9 we have | -9-6| = 15 true
for x= 21 we have | 21 -6| = 15 true
so A is a solution set
for x= -15 we have | -15-6| = 15 false
so B is not a solution set
for x= 9 we have | 9-6| = 15 false
so C is not a solution set
for x= -9 we have | -9-6| = 15 true
for x= -21 we have | -21-6| = 15 false
so D is not a solution set
for x= -6 we have | -6-6| = 15 false
so E is not a solution set