Identify the INCORRECT statement about spread strategies created by trading options of the same type $($either all calls or all puts$)$ on the same underlying with identical terms $($unless noted otherwise$)$:

a$.$ Vertical spreads $($also called money, perpendicular, or price spreads$)$ are established by buying one option and selling another option with a different strike price.

b$.$ Horizontal spreads $($or$,$ time or calendar spreads$)$ are established by buying one option and selling another option with the same strike but different maturity dates.

c$.$ Diagonal spreads are established by buying one option and selling another option that differ both in terms of strike price and maturity dates.

d$.$ A butterfly spread is created by trading four options with three different strike prices: two options with extreme strike prices are bought $($written$)$ and two options are written $($bought$)$ with the middle strike price.

e$.$ A condor spread is created by trading four options with three different strike prices: two options with extreme strike prices are bought $($written$)$ and two options are written $($bought$)$ with the same middle strike price.