Below are two statements:
Statement I: In a sample of wastewater, the total solids (dissolved and suspended) left after the water has evaporated are the residues.
Statement II: The dissolved solids typically include colloidal particles.
Based on the above statements, select the most appropriate answer from the options given below:

Correct option is A

Statement I: In a sample of wastewater, the total solids (dissolved and suspended) left after the water has evaporated are the residues. This statement is correct, as it accurately describes how total solids in wastewater are measured. The residue left after evaporation includes both dissolved and suspended solids.
Statement II: The dissolved solids typically include colloidal particles. Although colloidal particles are generally considered a separate category due to their size, which is between dissolved ions and suspended particles, they can sometimes behave like dissolved solids in certain contexts, especially in wastewater treatment, where they do not settle out easily and can pass through filters designed to remove larger suspended particles.
Hence, Both Statement I and Statement II are correct.