Final answer:
Excess insurance is the correct term for insurance that provides additional coverage beyond the underlying policy's limits for the same risk but on a different coverage basis, differing from concurrent, contributory, and non-contributory insurance.
Step-by-step explanation:
The term that refers to other insurance that is written on the same risk, but not on the same coverage basis, is B. Excess insurance. Excess insurance provides additional coverage beyond the limits of an underlying policy or policies. Unlike concurrent insurance, which involves multiple policies that cover the same risks and perils to the same extent, excess insurance only kicks in after the limits of the underlying policy are exhausted.
It is different from contributory insurance, where two or more policies with identical coverage pay on a claim, and non-contributory insurance, where the insured party is not responsible for paying premiums.