The lakes mostly covered with ice is:

Correct option is C

Correct Answer: (c) Amictic
Explanation:
→ Amictic lakes remain permanently ice-covered (typically polar or very high altitude lakes) and therefore do not undergo seasonal mixing.
→ Ice cover prevents wind-driven circulation and vertical mixing.
Information Booster:
→ In contrast, dimictic lakes mix twice a year (spring and autumn), polymictic mix frequently, and oligomictic mix rarely.
Additional Information (Other Options):
(a) Oligomictic: mixes infrequently.
(b) Dimictic: seasonal mixing twice a year.
(d) Polymictic: frequent mixing, not ice-covered.