Which of the following is a commonly used concrete mix?

The commonly used concrete mix in the provided options is characterized by its proportion of components: 1 part cement, 2 parts sand, and 4 parts gravel. This mix achieves a balance that provides strength and durability, which are essential qualities for concrete used in a variety of construction applications.

Concrete mixes typically follow a standardized ratio to ensure the concrete attains the desired strength properties and workability. The mix of 1:2:4 is a widely recognized formulation, often resulting in a concrete strength suitable for most structural uses, including foundations, slabs, and various outdoor surfaces.

Cement acts as the binder, while sand contributes to the workability and helps achieve a fine texture. Gravel, being the coarse aggregate, provides bulk and increases the strength of the concrete through its structural integrity when combined with the other ingredients. The proportions in option B are conducive to optimal performance in concrete, making it the correct choice. This mix ratio often correlates to approximately a compressive strength of around 3000 PSI when properly cured, making it ideal for many construction projects.