Question

Go back ____ you came.
a. where
b. when
c. whence
d. whither​

Answer 1

Answer:

From where

Explanation:

The question should be "Go back from where you came".

Answer 2

Answer:

Go back whence you came.

”Whence,” “Where,” and “Whither” are all adverbs, although some people erroneously treat them as pronouns; thus, “to where,” “from whence,” etc. All erroneous or redundant usages.

The use of “where” as a pronoun has become so widespread that “whence” and “whither” have become archaic; although “Where are you going?” is perfectly clear, many people insist on submitting “Where are you going to?” You would think that, if they wanted more clarity, they would give “whither” a chance.

To your specific question, “from whence you came” is an improper redundancy. Simply “whence you came” has everything patched up and working.