Black Scholes option pricing formula. We suppose that the current price of a share of General Electric is $$100.$ The current risk$-$free interest rate is $3\%$ and the standard deviation of changes in GE share prices is $20\%.$ The spreadsheet shows the prices of call and put options for a variety of strike prices.

If you raise the current price of GE's shares to $$105,$ what happens to the values of the calls and the puts? Why does this happen?

If you raise the standard deviation of GE's shares to $0\mathrm{.}23(23\%),$ what happens to the values of the calls and the puts? Why does this happen?

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If you raise the time until expiration to $3$ months $($a quarter of a year$),$ what happens to the values of the calls and the puts? Why does this happen?