Step 1: Understand the properties of stoneware.
Stoneware is a type of ceramic that is fired at a high temperature (typically between 1100°C and 1300°C). This high firing temperature causes the clay particles to fuse together in a process called vitrification.
Step 2: Relate vitrification to physical properties.
Vitrification makes the ceramic body dense, hard, and non-porous (impermeable to water). Therefore, stoneware is characterized as being hard, fired, and non-porous. Options describing softness and porosity refer to lower-fired ceramics like earthenware or unfired clay.