If you're scanning black/white negative film, first check to see if the film looks gray or orange to the naked eye. If it looks gray, set "Input|Media type" to "B/W negative" and if it looks orange, set it to "Color negative". Then go to the Color tab and choose a Black/White film type. If you can't find a film type that exactly matches the film you're using, experiment with the Kodak T-Max settings.
On most scanners, setting "Input|Media type" to "Color negative" will increase the green exposure time by 2.5x and the blue exposure time by 3.5x. This results in adjusting for the green and blue absorption by the orange mask of the film. If the film doesn't have an orange mask, then using "Color negative" will result in a raw scan file that looks very, very cyan.