Which of the following are the two bases for mastics?

The correct answer identifies the two primary bases for mastics as water-based and solvent-based.

Mastics are sealants or adhesives used in construction and maintenance applications. Water-based mastics use water as a carrier or solvent, which makes them easier to clean up while still wet, reduces potential odors during application, and can be less harmful to the environment when compared to solvent-based options. They typically dry through the process of water evaporation.

On the other hand, solvent-based mastics utilize organic solvents, which can provide advantages in terms of adhesion and flexibility. These products often perform better in a wider range of temperatures and humidity levels and tend to cure more rapidly after application. However, they can present challenges such as stronger odors and potential health concerns due to volatile organic compounds (VOCs).

Understanding these bases is fundamental for selecting the appropriate mastic for specific environmental conditions and application needs. The other options reference combinations that do not accurately represent the primary classification of mastics based on their bases.