Question

When used in the preterite tense, the verb "saber" means

Answer 1

When used in the preterite tense, the verb "saber" means to find out.

In a present tense, ther verb saber would mean to know. However, It can change its meaning when conjugated in its preterite form: supe or sabía.

In this case, "supe" in English could be translated as found out into English when refering that you learnt or got specific information about a person or about something.

Answer 2

"Saber" in the preterite tense means to find out. 
option C is correct
hope this helps