What was " doing our bit"?

a. doing what you could to the war effort

b. working to promote the four freedoms

c. working in war production

d. buying war bonds

This is tricky. It could be either A or D. It would definitely have to do with buying war bonds, but it also has to do with helping in whatever way you can for the war (i.e. Not eating bread on certain days, working extra hours building missiles, buying war bonds, etc.) because buying war bonds is more specific than just "helping out in whatever way", I would say that it is A.

Hope I helped! :) (would you mind giving Brainliest? I'm trying to increase my title. I'd really appreciate it!)