Final answer:
To find out how many years a ruby has been underground when buried 4.28 centuries ago, we multiply 4.28 by 100 (since 1 century equals 100 years) which equals 428 years.
Step-by-step explanation:
When calculating the number of years a ruby has been underground from 'centuries', it is necessary to use the information that 1 century equals 100 years. Given that the ruby has been buried for 4.28 centuries, the calculation to convert centuries to years would be:
4.28 centuries × 100 years/century = 428 years
Therefore, the correct answer is A) 428 years. The ruby has been underground for 428 years since it was buried by the ancient Romans.