I am preparing a QuantFinance lecture and I am looking for the easiest and most accessible derivation of the Black-Scholes formula (NB: the actual formula, not the differential equation).
My favorite at the moment is
Intuitive Proof of Black-Scholes Formula Based on Arbitrage and Properties of Lognormal Distribution by Alexei Krouglov
which uses the truncated or partial lognormal distribution.
I would love to see derivations which are even easier - Thank you!
The course is for beginners. It is business administration, so the math level is undergraduate.