What is the benefit of exploratory lines in a study sketch?

They help search form, proportion, and movement

Exploratory lines are light, temporary marks made while an artist studies a subject and searches for the best drawing. They are not necessarily part of the finished outline. An artist may use them to test where a form should be placed, how large it should be, whether its proportions look balanced, and how its movement or gesture can be shown. Such lines support observation and decision-making before darker final lines are added.

Thus option A is correct: exploratory lines help search form, proportion, and movement. They are useful precisely because they can remain flexible and can be corrected or covered later. Option B is false because these lines do not always spoil a drawing; in a study sketch they are often valuable evidence of the thinking process. Options C and D are unrelated: lines cannot make paper invisible or make colours permanent. Their educational purpose is to help the artist analyse and develop the subject.

This is a Class 9 Art Education question. Chapter: Elements of Art. Topic: Line.