In the context of Octavia's pattern of playing one note in the first measure followed by two notes in the second measure, it seems she is dividing the measures into different rhythmic values. Given the options provided, the most likely choice for the notes she plays in the second measure is quarter notes. This is because playing two quarter notes in a measure is a common practice and gives a clear, rhythmic feel that contrasts nicely with the single note in the first measure.
Thus, the answer is: quarter notes.