The correct answer is option 4, which states that all the statements are true.

Statement 1: Universal indicator is indeed a mixture of several indicators. It is a combination of different pH indicators that cover a wide range of pH values. This allows it to provide a more accurate and complete representation of the pH of a solution.

Statement 2: Universal indicator is capable of showing different colors at different concentrations of hydrogen ions in a solution. It changes color depending on the pH of the solution, with each color representing a different pH value.

Statement 3: Universal indicator is frequently used in titrations to determine the strength of acids and bases. It helps to visually observe the endpoint of the titration, which is the point at which the acid and base have completely reacted. By noting the color change of the universal indicator, we can determine the pH of the solution and hence the strength of the acid or base.

In conclusion, universal indicator is a mixture of several indicators, shows different colors at different concentrations of hydrogen ions, and helps determine the strength of acids and bases in titrations.