[Listening extract audio not available in printed QP] The first movement is in sonata form. The exposition begins with the first subject in G major. (a) In ...

(a) The correct answer is D major (the dominant). [1]

In sonata form, when the first subject is in a major key, the second subject is conventionally presented in the dominant key (the key a fifth higher). Since the first subject is in G major, the dominant key is D major. This key contrast between tonic and dominant creates harmonic tension that drives the exposition forward and provides material for development and eventual resolution. If the first subject were in a minor key, the second subject would typically appear in the relative major instead. This tonal relationship is one of the fundamental structural principles of sonata form.

(b) The correct answer is a transition (also called a bridge passage). [1]

The transition (or bridge passage) is the connecting passage between the first and second subjects in a sonata-form exposition. Its primary function is to modulate (change key) from the tonic key of the first subject to the new key of the second subject. Transitions often feature sequential passages, increased rhythmic energy, or fragmentation of the first subject's material. They build harmonic momentum that propels the music into the second subject. The transition is an essential structural element that creates a sense of movement and direction between the two contrasting thematic areas.