meaning of 'For the good of mankind'

[Silke]

English Language Tests, Intermediate level

ESL/EFL Test #253 "Good, Well and Okay Test (1)", question 1

We should strive for world peace for the ......... of mankind.

(a) good
(b) well
(c) okay

English Language Tests, Intermediate level

ESL/EFL Test #253 "Good, Well and Okay Test (1)", answer 1

We should strive for world peace for the good of mankind.

Correct answer: (a) good
_________________________

what's the meaning"good" in this sentences?
let me know the meaning of"good"in the circumstances

Silke

[Conchita]

'For the good of mankind' means 'for the benefit of mankind'.