Have you tried cleaning and repacking the BB yet? It may still be okay if it gets cleaned out. Or it might have the bearing races pitted, in which case it should be replaced.
Assuming the BB is the proper dimensions you could just get a replacement with the same spindle length and (a)symmetry. You want the center chainring of a triple 45mm from the bike frame's centerline, or the midpoint between two chainrings of a double 43.5mm from the bike's centerline. Also, bottom brackets aren't always symmetrical, and you want both pedals equidistant from the bike's centerline.
I've got a 1987 Centurion Ironman Expert that came with Shimano 105 double crank and a 110mm symmetrical bottom bracket. Problem is, Shimano-compatible cartridge bottom brackets that are 110mm spindles are asymmetrical, with the non-drive-side sticking out further than the driveside (driveside spindle length of the 110 is same as the Shimano-compatible 107mm).
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"c" is not a unit that measures tire width