Yes, pH of the soil affects the colour of flower.
Flowering plants grown in acidic soil (pH<7) bears blue flowers or at has a blueish tint.
Whereas, Flowering plants grown in Neutral (pH=7) and Basic (pH>7) soil bears pink and red flowers.
A plant's flower color is determined by a complex balance between chlorophyll, beta carotene, flavonoids,etc in particular pH of the soil to give out vibrant colors like red, blue, pink, yellow,etc.
B) A disease can destroy everything
I think it's A not sure tho
D. Protein
Carbohydrates are made from three elements known as Carbon, water, and oxygen.
DNA is made up of phosphate sugar groups for the helix and nitrogenous bases for the inside.l
Lipids also are only made form carbon, water, and oxygen but in a different ratio.