I am really confused weith sig. figs. and it would really help if someone could check my answers. My answers are after each problem

Determine the number of sig. figs. in the following

(a)12.7040g - 6
(b)200.0 cm - 4
(c)276.2 tons - 4
(e)4.00 x 10^3 - 3
(f)100 degrees C - 1