Explanation:

The cement content in concrete plays a vital role in determining its strength and other properties. The correct answer to the given question is option 'D', i.e., higher cement content leads to higher strength. The following points explain the same:

Higher cement content:

- Cement is the primary binding material in concrete, responsible for holding the aggregates together. Hence, increasing its proportion in the mix leads to more binding and thus, higher strength.
- However, it is essential to note that adding too much cement can result in a brittle and less durable concrete, which may crack or develop other defects over time.
- Moreover, higher cement content also leads to higher cost, as cement is usually the most expensive component in the concrete mix.

Impact on aggregates:

- The aggregates in concrete are typically composed of sand, gravel, or crushed stone, and they provide bulk and stability to the concrete.
- Increasing the cement content does not necessarily mean increasing the aggregate content. In fact, too much cement can cause the mix to become too sticky and difficult to work with, reducing the ability to incorporate the aggregates properly.
- Hence, higher cement content does not necessarily lead to higher aggregate content.

Impact on workability:

- Workability refers to the ease with which the concrete mix can be placed, compacted, and finished. It is an essential property for achieving a smooth and uniform surface and avoiding defects such as honeycombing, bleeding, or segregation.
- Increasing the cement content can reduce the workability of the mix, making it stiffer and harder to move around. This can make it challenging to achieve a suitable finish and may require more effort from the workers.

Conclusion:

In summary, the correct answer to the given question is option 'D', i.e., higher cement content leads to higher strength. However, it is essential to balance the cement content with other factors such as aggregates, water, and workability to achieve a concrete mix that is strong, durable, and easy to work with.