Concept:The word "theoretical" is contrasted with "practical" in this sentence.
"Practical aspects" refer to real-life application or hands-on performance.
Explanation:Theoretical exercises deal with ideas and understanding in the mind.
However, carrying them out in real situations can be hard.
"Practical" means involving actual doing or physical action.
"Actual" and "natural" do not form the correct opposite pair here.
"Logical" relates to reasoning, not to hands-on application.
Therefore, the missing word that best fits is "practical."
Answer:B. practical