Items that have a "pH level of 1" would be considered a "strong acid".
Option: C
Explanation:
pH scale is useful for accounting acidic or basic behavior of liquid solutions. pH scale starts from 1 to 14 and each number represents the "concentration of hydrogen ions" in the solution like lower pH showcase "higher concentration of hydrogen ions" but higher pH is indication of "lower concentration of hydrogen ions" and measured logarithmically. Scale represents 0 to 6 as Acidic, 7 as neutral and 8 to 14 as basic pH . For example "battery acid" is most acidic, blood is neutral and liquid drain cleaner is most basic.