The period of 400 AD to 1600 AD is considered as classical period of Indian Mathematics, though it emerged in the Indian subcontinent from 1200 BC. The decimal number system and the concept of zero as a number was first recorded in Indian mathematics. Indian mathematicians made early contributions to the study of arithmetic, algebra, and trigonometry. In addition, the modern definitions of sine and cosine were developed here. Ancient and medieval Indian mathematical works, all composed in Sanskrit, usually consisted of a section of sutras in which a set of rules or problems were stated with great economy in verse in order to aid memorization by a student. This was followed by a second section consisting of a prose commentary (sometimes multiple commentaries by different scholars) that explained the problem in more detail and provided justification for the solution. In the prose section, the form was not considered as important as the ideas involved.

Excavations at Harappa, Mohenjo-daro and other sites of the Indus Valley Civilisation have uncovered evidence of the use of practical mathematics. They used a standardised system of weights based on the ratios: 1/20, 1/10, 1/5, 1/2, 1, 2, 5, 10, 20, 50, 100, 200, and 500, with the unit weight equalling approximately 28 grams, approximately equal to the English ounce or Greek uncia. They mass-produced weights in regular geometrical shapes, which included hexahedra, barrels, cones, and cylinders, thereby demonstrating knowledge of basic geometry. The inhabitants of Indus civilisation also tried to standardise measurement of length to a high degree of accuracy. They designed a ruler called as the Mohenjo-daro ruler, whose unit of length (approximately 1.32 inches or 3.4 centimetres) was divided into ten equal parts. Bricks manufactured in ancient Mohenjodaro often had dimensions that were integral multiples of this unit of length.

I. The decimal number system was first used by the mathematicians based in 

i. Greece 

ii. Indian subcontinent 

iii. England 

iv. elsewhere.

II. In ancient and medieval Indian mathematics, 

i. a formula was written in the form of Sanskrit verses 

ii. a formula was explained as prose 

iii. both i and ii 

iv. neither of i and ii.

III. People of Indus Valley Civilisation 

i. were good at using basic geometry 

ii. developed the system of units for measuring mass and length 

iii. both i and ii 

iv. neither of i and ii.

The correct answers to I, II and III are: 

A. ii, iv and iv, respectively 

B. iv, i and ii, respectively 

C. i, ii and iii, respectively 

D. ii, iii and iii, respectively.