Mapping: Help W/ Lighting 2

[JeeMonkey]

hey all, im a beginer mapper and i got a question about lighting. when i am trying to change the radius of a spot light, what is 1 unit equal to? is it....

A) 1 unit on grid .25

B) 1 unit on grid .5

C) 1 unit on grid 1

D) 1 unit on grid 2

E) 1 unit on grid 4

F) 1 unit on grid 8

G) 1 unit on grid 16

H) 1 unit on grid 32

I) 1 unit on grid 64

J) 1 unit on grid 128

K) 1 unit on grid 256????????

[Prime]

I'd take this question to the mapping forum 2...