Clearly there is only one correct choice here, Nunally and have someone dispose of Rolo while he sleeps.

for some reason, the fact that nunally has her eyes open and is actually showing some kind of emotion in this picture totally changed my opinion of her

Nunally wore the wrong uniform. Supposed to be the pink one. Maybe that's for the middle high schoolers or something. (or lolis - anya also wore pink school uniform)