Arbitration - Riskless Income from Stock Market

#1
Stock Market is not only meant for Risky investments but from some relaible sources I have also come to know that Arbitration can help investors earn Riskfree income from Stock Market. given below are some techniques I welcome all to verify the claims made here so that fellow investors can know more about this little known phenomenon:

A) I can arbitrate between Stocks and Nifty Futures
B) I can arbitrate between Buy and Sell Spread in Futures Market
C) I can arbitrate between Bid and Ask in futures market to gain more than Riskfree rate of return.
D) By realising difference between Put Call PArity
E) By Realising Parity between Futures and Options.

Regards
 
#2
Please Explain the method how arbitration can be realized between the buy and sell spread in future market