Answer:
Option B. Made advances in medicine
Step-by-step explanation:
Option A is not correct as Greek city-states were having slaves, even Athens which was regarded the most democratic state.
Option B is correct as medicine developed in Greece a lot, especially with Hippocrates who is regarded as a father of medicine.
Option C is not correct as Hellenistic Kingdoms were defeated by the Romans.
Option D is not correct as the first written letters appeared in Mesopotamia.