The correct answer is C, A unit investment trust (UIT). Under the Investment Company Act of 1940, an investment company is defined as a company that pools investor funds to invest in securities portfolios. UITs are one of the three types of registered investment companies, along with mutual funds (open-end) and closed-end funds.
Step-by-step, a UIT is a fixed portfolio of securities that is professionally selected but not actively managed. Once created, the portfolio generally remains unchanged for the life of the trust. Investors purchase units representing an ownership interest in that portfolio.
Choice A, a variable annuity, is an insurance product, although it may invest in subaccounts that resemble mutual funds. Choice B, a private equity fund, is typically privately offered and exempt from registration under the Investment Company Act, so it is not considered a registered investment company. Choice D, a REIT, is a company that invests in real estate and is not classified as an investment company under the Act.
Thus, among the choices, only a UIT qualifies as a registered investment company, making Answer C correct.