What is the main basis of Numerical Taxonomy?

Correct answer: Statistical analysis of all observable characters using computers

Numerical taxonomy classifies organisms by measuring many observable characters and comparing the resulting data mathematically. Instead of depending mainly on one selected feature, it records a large number of traits, often gives them comparable importance, and uses statistical methods—commonly with computer assistance—to calculate similarities and differences. The results may be shown in a numerical table or a similarity-based grouping. This approach makes classification more systematic and less dependent on one person’s subjective choice.

Therefore, B is correct: it is the statistical analysis of all observable characters using computers. Option A is too narrow because numerical taxonomy does not rely on only one character. Chemical properties alone are not its complete basis, and colour is only one possible observable trait. The method is useful because many characters together provide stronger evidence for comparing organisms than a single appearance-based feature.