Commercial forestry tried to make the supply of what regular?

Correct answer: Timber

The direct answer is C: timber. Commercial forestry means managing forests mainly to produce marketable forest goods, especially useful wood. Step by step: colonial governments needed wood for railways, ships, buildings, fuel, and other projects; natural forests did not always provide a predictable supply of the desired species; officials therefore planned cutting and replanting; regular production and supply of timber became a major aim. Option A, salt, comes mainly from seawater or salt-producing areas and is not the central product of commercial forestry. Option B, cotton, is an agricultural fibre grown in fields, not the main forest product targeted by this policy. Option C is correct because timber means wood prepared for construction, railway sleepers, ships, or other commercial uses. Option D, pearls, come from oysters and are not supplied through forestry. The word regular is important: commercial forestry was not merely random tree cutting; it involved scientific management, selected species, planned plantations, and controlled production for steady supply. Memory cue: commercial forestry = forests managed like production areas, especially for regular timber.