Consider the following equation:\[ C = C_1 + C_2 - C_1C_2 \]where \( C \) stands for the fractional cover of a fabric, \( C_1 \) denotes the fractional cover of warp, and \( C_2 \) refers to the fractional cover of weft. Amongst the given options, the fabric structure(s) in which the aforesaid equation is valid is/are.