In lithostratigraphy, a Group is a stratigraphic unit that consists of two or more formations. It represents a larger-scale classification based on lithological properties of rocks, such as their composition, color, texture, and formation process. A Group can contain multiple formations, which in turn may contain members or beds.
- Sequence stratigraphy (B) deals with the analysis of sedimentary sequences based on depositional environments, not with the classification of rocks by their physical properties.
- Biostratigraphy (C) focuses on the use of fossil organisms to define and correlate stratigraphic units.
- Chronostratigraphy (D) refers to the dating of rocks and their correlation with geologic time, rather than their physical composition.
Thus, the correct answer is (A) Lithostratigraphy.