The figure shows the amount of water in a graduated test-tube. The curved surface shown is called the meniscus. What is the correct reading of the volume of liquid A 7.1 ml
B 7.2 ml
C 6.8 ml
D 6.6 ml

Answerboth technicians (a) and (b);

It really doesn't matter for any of the questions that you've listed.

Supply is the markets term for selling a specific quantity of products at various prices. the law of supply and demand is the one which affect the pricing and also the quantity the market is able to produce or make available.