Am pretty sure the correct answer is C.
Nora has a flirtatious behavior that suggests that Helmer and she have a flirtatious but stable relationship but sometimes it is serious. Helmer supports the careless attitude of Nora with money and he also worries and criticizes her habit of squandering money to make her understand the value of saving. This behavior shows that there is still a lot of love in their relationship and that it is not a couple with a bad mood.
The sentence - The poll was conducted by volunteers - is written in the passive voice. The correct answer is B.
The active voice would be - Volunteers conducted the poll.
