Step 1: Understanding the Question:
We must name the medium (the material and paint type) used in the Mughal painting 'Madonna and Child'.
Step 2: Work from the general rule:
Almost every Mughal miniature uses pigments bound with gum on prepared paper. The paint is opaque, meaning the colour does not let the paper show through. Even when Mughal painters copied Christian themes, they kept their own medium.
Step 3: Rule out later or foreign media:
Oil on cotton is a European method that Indian court painters of that time did not use. Wash on paper belongs to the Bengal School in the twentieth century.
Step 4: Separate paper from cloth:
Cotton supports were used for a few special works, but the Madonna and Child is a normal album page on paper. So paper is the support.
Step 5: Conclusion:
Opaque watercolour on paper matches both the Mughal tradition and this painting, so option (1) is correct.
Step 6: Cross-check the other options.
Option (2) names cotton, a support used for a few large cloth pieces and not for album pages like this one. Option (3) names wash, a method of the Bengal School, which came about three centuries later. Option (4) names oil on cotton, which Mughal painters did not use. Only option (1) matches both the period and the studio practice.
Final Answer:
Option (1), opaque watercolour on paper.