* 4L60E: A four-speed automatic overdrive transmission. This was the most prevalent option.
* 700R4: A four-speed automatic overdrive transmission; less common than the 4L60E by 1993.
* SM465: A four-speed manual transmission. This was available, but less frequently chosen than the automatics.
* NV3500: A five-speed manual transmission; also available, but not as common as the 4L60E automatic.
To know for certain which transmission a *specific* 1993 Chevy C1500 had, you'd need to check the vehicle's documentation (owner's manual, build sheet) or look at the transmission itself.