For a put-call parity,

put + stock price = call + pv(strike price)

P + S = C + PV(X)

if:

836.52 + 26.71 = 23.87 + 840e^(-0.055*1/12)

863.23 =/= 860.02

and therefore has an arbitrage of $3.21

However, how is this arbitrage profit affected if the cost per stock is $10 and the cost of an options trade is $25?