Observe the following statements. Select the correct one.
(a) Temperature increases progressively from equator towards the poles and from plain to mountain tops.
(b) Temperature is sub-zero level in polar areas and high altitude and increases to above 50°c in tropical desert in summer.
(c) In unique habitats such as thermal springs and deep sea hydrothermal vents average temperatures exceed 20°c.
(d) Mango trees grow in temperate countries like Canada and Germany.