Acontext clue of direct explanation or synonym may often be found: select all that apply.

a. at the front of the sentence

b. following the unfamiliar word

c. set off by commas or other punctuation

d. following words such as that is

e. in the dictionary or thesaurus

I'll select B and C.
B.following the unfamiliar word
C.set off by commas or other punctuation

Atahualpaemperor of the inca empire who rose to the throne after winning a civil war between him and his brother.  -he refused to become a spanish vassal or christian.-francisco pizarro kidnapped him and demanded a huge ransom.  -pizarro's secretary described him as "a man of thirty years, good-looking and poised, somewhat stout, with a wide, handsome, and ferocious face, and the eyes flaming with blood."-after the ransom was paid, atahualpa was killed by pizarro