Answer:
The correct answer is option C.maestro-agradables.
Step-by-step explanation:
In Spanish, adjectives must match in gender and number with the noun to which they are giving the qualifier.
In this case we have a singular word: maestro and a plural adjective that accompanies it: agradables. Together they do not form a correct description.
The correct way would be:
Maestro agradable.
or
Maestros agradables.