Answer:
In order to actually compare two objects in a comparison of inequality (one object being more or less ____ than the other), we use the following construction: subject + linking verb + más/menos + adjective + que + noun.
Explanation:
9. Mientras Enrique _C. tocaba
_ la guitarra, Carmen cantaba.
11. San Sebastian sits on B. the Bay of Biscay.
12. Juan Tomas Avila Laurel went on a hunger strike to protest A. the presidents regime in Equatorial Guinea
19. Yo _D. compré_ in libro y despues fui a casa.
It is not C. compró because I just took a test that has that same exact question and I put down C. compró and I got it wrong. So I thinks it's D. compré.
Las ciencias fisicas
Explanation: from SpanishDict
Estoy leyendo un libro muy interesante.
The answer is leyendo.