Which of the following is incorrect about trading activities?

Risk arbitrage involves buying securities in anticipation of some information release (for example, a merger or takeover announcement).

Pure arbitrage involves buying an asset in one market at one price and selling it immediately in another market at a higher price.

Position trading involves direct access, via the Internet, to the trading floor, therefore bypassing traditional brokers.

Stock brokerage involves trading securities on behalf of customers.

Program trading is the simultaneous buying and selling of a portfolio of at least 15 different stocks valued at more than $1 million, using computer programs to initiate such trades.