Final answer:
The correct preposition to fill in the blank is 'encima'. It means 'on top of' or 'above' in Spanish.
Step-by-step explanation:
The correct preposition to fill in the blank is A. encima. Therefore, the sentence should be 'La pizarra está encima de la profesora Hernández.'
The word 'encima' means 'on top of' or 'above' in Spanish. In this context, it indicates that the blackboard is positioned above or on top of the teacher.
For example, one could say 'El gato está encima de la mesa' (The cat is on top of the table) to describe the cat's position relative to the table.
Learn more about Prepositions in Spanish