Which of the following statements is true? a. All well-rounded clasts are also spherical. b. Conglomerate consists of a single grain size. c. A well-sorted clastic rock is made up of a wide range of particle sizes. d. Pieces of broken rock produced by physical weathering are called clasts.

Option (D)

Explanation:

Clastic sedimentary rocks are usually defined as those rock that are made up of broken fragments of pre-existing rocks. For example, Conglomerate, Sandstone and Shale.

This rocks undergoes physical weathering processes and results in the breakdown. The broken fragments of rock and other material that are produces from this are commonly known as clasts.

This term "clast" is used for the sedimentary rock types in the field of geology.

Thus, the correct answer is option (D) - which is True.