Fill in the blank with the appropriate answer:
The government has created a new system of pension for __________.
It is to be noted that adjectives are used commonly to represent nouns in certain sentences. This usage is called ellipses of the noun phrase, wherein the shortening of a noun phrase occurs. The article ‘the’ becomes a crucial addition that converts the adjective into a noun that represents a group in general. Thus ‘the old’ is the apt answer because here ‘the old’ is used to shorten the noun phrase ‘the old people’. Hence option B is correct. Whereas ‘old’ is solely an adjective which cannot complete the meaning of the sentence because it should be filled with a noun. Thus option A is incorrect. Whereas, ‘an old’ cannot be used because the sentence speaks about the system benefiting all the old people, i.e. as a group, while ‘an old’ denotes just one individual. Hence option C is incorrect. Lastly, the answer cannot be ‘young’ because ‘pension’ is issued only for old people. Thus option D is incorrect.