In Which of the Following Situations Is a Corporation Earning

In which of the following situations is a corporation earning incidental property income?

A) Regina Corporation has built up its cash reserves over several years, and its staff invests this surplus cash in a variety of publicly traded corporations, earning dividend income. This income is approximately 10 percent of corporate income on an annual basis.
B) A branch of Moose Jaw Corporation invests surplus cash for 2-3 months every year earning interest income which is less than 1 percent of corporate income.
C) Saskatoon Corporation has one rental property which is leased to a retail outlet. The net rental income from this property is 5 percent of corporate income.
D) Lethbridge Limited sells its factory building resulting in a capital gain which is about 10 percent of corporate income.