The best way to solve this is by giving a visual idea of the glass ornaments. so We will have letter G represent Green, O for Orange, B for Brown, P for Purple.
Sample 1:G,O,B,P
Sample 2:G,P,O,B
Sample 3:P,G,O,B
Sample 4:O,G,P,B
Sample 5:G,O,P,B
This is what you can do this should be the right amount of ways to arrange them.
Answer:
B
Step-by-step explanation:
Well since it is arthimetic sequence we know the formula
We know d is difference between second term and first so it will be -5- (-12)= -5+12= 7

the domain of this is 1,2,3,4.......
range is -12,-5,2,9.......
Therefore answer is B.