Which scale degree functions as the leading tone in Western harmony?

• A. Fifth
• B. Seventh
• C. Third
• D. Second

Answer: (B)

The leading tone is the seventh degree of the scale. In Western harmony, it has a strong pull to resolve upward by a half step to the tonic, creating a classic sense of tension resolving to rest. For example, in C major the note B tends to move up to C, signaling the home pitch is arriving. In minor keys the leading-tone function is reinforced by raising the seventh scale degree in the harmonic minor scale, again guiding voices toward the tonic. This is why the seventh is the best answer: it uniquely provides that direct upward pull to the tonic. Other degrees play different roles and don’t carry this specific leading-to-tonic tendency.