The correct answer is C. Finer grinding of cement affects both the early development of strength and the ultimate strength.
Cement is a fine powder that is used to make concrete. The strength of concrete is determined by the strength of the cement paste, which is the mixture of cement and water. The finer the cement is ground, the more surface area it has, and the more water it can absorb. This results in a stronger cement paste, and therefore a stronger concrete.
The early development of strength is the strength of the concrete at an early age, typically within the first few days or weeks. The ultimate strength is the strength of the concrete at its final age, typically after 28 days. Finer grinding of cement increases both the early development of strength and the ultimate strength.
Option A is incorrect because finer grinding of cement affects both the early development of strength and the ultimate strength. Option B is incorrect because finer grinding of cement affects both the early development of strength and the ultimate strength. Option D is incorrect because finer grinding of cement does affect the strength.