Clues Mona was A →  2x24

It obviously wasn’t Melissa (because when are the PLLs ever right?) so that left Caleb or Mona.

Clues Mona was A →  2x19

Now we know what Mona’s third personality was.

Clues Mona was A →  1x16 & 2x10

Mona must have learnt French recently, as Hanna was surprised to hear her speaking it.

MW