Final answer:
Talc is primarily composed of the mineral talc, which is a complex silicate containing silicon-oxygen bonds in formations like rings, sheets, or three-dimensional networks, and may include cations like calcium, magnesium, and iron.
Step-by-step explanation:
Talc, also known as a complex silicate, is primarily composed of the mineral talc which contains a silicate compound with silicon-oxygen bonds. These silicate tetrahedra can be connected in various forms such as rings, sheets, or three-dimensional networks. In silicates, silicon atoms are usually sp³-hybridized and situated at the centers of tetrahedra with oxygen atoms occupying the corners. Additionally, the presence of other cations such as calcium, magnesium, and iron contributs to the diversity of silicate minerals.
For example, quartz (SiO2) is a crystalline form of silica, and rapid cooling of molten SiO2 yields an amorphous solid known as fused silica.
Therefore, the correct answer is a) Composed of talc.