IBPS PO Prelims 2020 - English Language

Directions (21-26): Given below is a paragraph that has blank spaces. Corresponding to each blank, five options are given, out of which only one is appropriate. Choose the option that fits most suitably in the given blank making sentence grammatically and contextually correct.

Gaseous refinery (21) include hydrogen, fuel gas, ethane, propane, and butane. Most of the hydrogen is (22) in refinery desulfurization facilities, which remove hydrogen sulfide from the gas stream and then separate that compound into elemental hydrogen and sulfur; small quantities of the hydrogen may be delivered to the refinery fuel system. Refinery fuel gas varies in composition but usually contains a (23) amount of methane; it has a heating value similar to natural gas and is consumed in plant operations. The drawback is that periodic variability in heating value   makes   it (24) for delivery to consumer gas   systems. Ethane may be (25) from the refinery fuel system for use as a petrochemical feedstock. In many cases, these operations take place in relatively remote regions and affect only those employed by the industry, so that little or no (26) is attempted.

Which of the following should be filled in place of 21?