Which one of the following is a derivative instrument?

Select one:

a.

An investor buys a dual listed share on the JSE and simultaneously sells it on the London Stock Exchange in order to take advantage of the price difference between the two exchanges.

b.

An option to buy Satrix 40 at a specified price in one months time.

c.

Unit trusts, which derive their value from the shares that the fund has invested in.

d.

Satrix 40, which derives its value from the returns of the top 40 shares listed on the JSE.