Select the most appropriate option that can substitute the highlighted segment in the given sentence.
I asked Rita that how far her school was.

Correct option is D

The most appropriate option that can substitute the highlighted segment in the given sentence is (d) how far her school was.
 The original sentence is in indirect speech, and it is a reported question. In indirect speech, we typically use the past tense when reporting a question.
 No conjunction is used, if a sentence in direct speech begins with a question (how/what/where/when) as the “question-word” itself acts as a joining clause.
 Therefore, "how far her school was" is the correct past tense form.
 The other options do not accurately represent the correct tense or structure of indirect speech.