Offer B canbe represented by an arithmetic sequence because there is a constant difference between the salary of two consecutive years.
The sequence can be written as follow:
Bn = 56,000 + 3,000n
where n is the number of years in the job.
By subtracting B(n+1) - Bn, you obtain:
As you can notice, the difference of the salaries between two consecutive years is constant, which means that Bn is an arithmetic sequence.