Which of the following describes a steel tape in the context of surveying?

A steel tape, often referred to as a chain in some contexts, is a common measuring device in surveying used primarily for linear measurements. Made from flexible steel, this tape can be rolled up for portability and is designed to provide accurate distance measurements over varying terrain. The term "chain" may also refer to traditional measuring devices that have links resembling chains, which is an early surveying method.

In contrast, the other options provided describe tools that serve entirely different functions in the field of surveying or construction. For example, soil composition determination involves other specialized equipment that is not related to linear measurement, while the calculation of angles pertains to instruments like theodolites or total stations, which are designed for measuring angles rather than distances. Similarly, pressure measurement instruments are used in different contexts like fluid mechanics or structural analysis, which again do not overlap with the primary function of a steel tape as a measure of length. Therefore, option B accurately captures the functional essence of a steel tape in surveying.