Of the options listed for 1, only investing in CDs is considered to not be a high-risk investment. The others are equity investments that contain no guarantee of security, whereas CDs are held with FDIC-insured banks.
With respect to question 2, the Dow Jones Industrial Average is a measure of aggregate performance of C, stocks. However, as a matter of clarification, it is not an exchange, but rather simply a collective performance measure.
