Concrete is produced by mixing which of the following ingredients?

Concrete is primarily produced by mixing Portland cement, aggregates, and water. Portland cement is a key binding agent that hardens and allows the mixture to gain strength over time. Aggregates typically consist of sand and gravel or crushed stone, which provide volume, stability, and compressive strength to the concrete.

Water is essential for the hydration process that activates the cement, leading to the setting and hardening of the mixture. The balance among these three components is crucial; too much or too little water can adversely affect the strength and durability of the concrete.

The other choices contain elements that may be found in certain concrete mixtures or alternative building materials, but they are not the standard components for producing traditional concrete. For instance, lime and soil in one of the options might be relevant in creating specific types of masonry or stabilization products but are not standard for the production of concrete. Similarly, while fly ash can be a supplementary cementitious material that enhances certain properties of concrete, it is not a defining ingredient in the fundamental concrete mix. Thus, the choice of Portland cement, aggregates, and water accurately reflects the classic definition of concrete ingredients.