The correct answer would be C
There aren’t any sentences?
1) c. estar a
2) b. estar a punto de
3) e.estar de vuelta
4) d. estar de acuerdo
5) a. estar de vacaciones
6) f. estar por
The question is asking about the setting of the book? Since you don’t have it posted I’d just scan through the beginning to try and determine the time & place
