Describe a potential conflict of interest in each of the following four situations:
a. An investment advisor whose compensation is based on commissions from client trades
b. An investment manager's use of client brokerage ("soft dollars") to purchase research or other services
c. A portfolio manager of a mutual fund who purchases, for the fund, a substantial amount of stock in a small-capitalization company whose warrants the manager owns
d. A research analyst who accepts reimbursement for food, lodging, and air transportation expenses for a site visit from the company on which she is writing a research report.