The draught or pressure difference for a chimney of height of H metres is given by?a) Δp = gH(ρa-ρg)b) Δp = gH(ρg-ρ

• A. Δp = gH(ρa-ρg)
• B. Δp = gH(ρg-ρa)
• C. Δp = gHρg
• D. Δp = gH(ρa+ρg)