The two ways of relating what a person has said are 1)direct and 2)indirect (reported speech).In direct speech, the original speaker's exact words are repeated. In indirect/reported speech, the exact meaning is expressed but not necessarily using the original speaker's exact words. Pronouns and possessive adjectives usually change from first or second person to the third person except when the speaker is reporting his own words. Sometimes a noun can be inserted to avoid doubt.
When we turn direct questions and exclamations into indirect speech, they are converted to affirmative statement .( ? and ! is not used).
Option C is correct as when we convert the given direct question to indirect speech which starts with a question word, then the question word is repeated, the present tense is changed to simple past tense (did),you to he, and to which is used to connect the two dialogues.
The other options are wrong as and , you, and went can't be used.
The correct answer is C)Sam asked Sue how often did he go away on holiday to which Sue replied one or twice a year.