Which of these sound like inflation, which sound like deflation, and which are ambiguous?

a. Gasoline prices are up 10%, food prices are down 20%, and the prices of most services are up 1–2%.

b. Gas prices have doubled, food prices are up 50%, and most services seem to be up 5% or 10%.

c. Gas prices havenʼt changed, food prices are way down, and services have gotten cheaper, too.