Final answer:
The self-employment tax consists of the Social Security portion and the Medicare portion. For 2015, the ceiling amount for Social Security is $118,500 with a tax rate of 12.4%, while the Medicare portion has no ceiling and a tax rate of 2.9%.
Step-by-step explanation:
The self-employment tax consists of two portions: the Social Security portion and the Medicare portion.
For the Social Security portion, the ceiling amount for 2015 is $118,500, which means that only income up to this limit is subject to the tax. The tax rate for this portion is 12.4%.
For the Medicare portion, there is no ceiling amount, so all income is subject to the tax. The tax rate for this portion is 2.9%.
Therefore, the correct answer is (a) $118,500; 12.4% Unlimited; 2.9%.