(c) Both 1 and 2
In Anoop Baranwal vs Union of India, the Supreme Court (SC) ruled that the appointment of the Chief Election Commissioner (CEC) and Election Commissioners (EC) by the President will be based on the advice of a three-member high-level committee.
Article 324 (2) – President shall with aid and advice of Council of Ministers, appoint CEC and ECs, till Parliament enacts a law fixing the criteria for selection, conditions of service and tenure.

(b) 1-3-2-4
Irrigation efficiency is the ratio between the amount of water used up by the crop to meet its consumption requirement and the amount of water needed to keep the salt balance in check. The depth and texture of the soil also have an important role to play.
When the soil is of the right depth and texture, fertilizers and minerals can evenly reach to the ground.
Clay has the highest proportion of organic matter. It has the highest porosity and lowest permeability. Therefore, the wet clods formed are highly stable.

(d) Poor soil drainage (both surface and internal)
• Saline and Alkaline Soils: These soils are liable to saline and alkaline efflorescence and are known by different names such as reh, kallar, usar, thur, rakar, karl and chopan. There are many undecomposed rock and mineral fragments which on weathering liberate sodium, magnesium and calcium salts and sulphurous acid. The accumulation of these salts makes the soil infertile and renders it unfit for agriculture. Saline soils have a pH between 7 and 8.5, while alkaline soils have a pH greater than 8.5.

(b) Microbial fixation
Microbial fixation is the process by which microbes fix nitrogen and carbon dioxide:
Nitrogen fixation: Microbes fix nitrogen by oxidizing organic molecules and requiring 16 moles of adenosine triphosphate (ATP) to reduce each mole of nitrogen. Nitrogen is a macronutrient that is part of proteins and nucleic acids. Microbes that fix nitrogen include Azotobacter, Bacillus, Clostridium, and Klebsiella.
Carbon dioxide fixation: Microbial fixation of carbon dioxide involves metabolic routes, genetic manipulations, and engineering of microbial hosts.

(c) A is true but R is false
Nitrogen is present in soil in the form of nitrates or nitrites, which plants can’t directly absorb. Nitrogen deficiency can cause yellowing and stunted growth. Soils in India are deficient in nitrogen.
Rocks contain varying concentrations of nitrogen, much of it in forms that organisms can use. Nitrogen in rock can come from organically bound nitrogen associated with sediment, or in thermal waters.