It's definitely the 15th. Google it for more details.
Make the denominators equal - Make 2 = 12
Multiply the fraction
by 6
Put together your new fraction, keep the right the same because denominator is already 12 (same)
Subtract the numerators
C. The Mycenaean civilization (c. 1700-1100 BCE) flourished in the Late Bronze Age, reaching its peak from the 15th to the 13th century BCE when it extended its influence not only throughout the Peloponnese in Greece but also across the Aegean, in particular, on Crete and the Cycladic islands