Select a suitable option to complete the sentence:
Diplomacy is the best means of ________ peace which a society of sovereign nations has to offer, but, especially under the conditions of ___ world politics and of contemporary war, it is not good enough.
a) maintaining, today’s
b) presenting, contemporary
c) retaining, present
d) promoting, modern
e) evolving, self-centred

Hint:A verb is a content word that denotes an action, occurrence, or state of existence. An adjective is a word that expresses an attribute of something.

Complete answer:
In the given question, we have to find the right verb for the first blank and the right adjective for the second.
Let us thus analyze the options given to us in this question:
Option (a.), 'maintaining, today’s', refers to the verb ‘maintain’ which means ‘causing to continue in a certain state, position, or activity’; e.g., `keep clean', and the adjective ‘today’s’ which means ‘of, pertaining to, or produced today’.
Therefore, option (a.) is correct as this verb and adjective fit perfectly into the sentence.

Option (b.), ‘presenting, contemporary', refers to the verb ‘presenting’ which means ‘bring forward and present to the mind’, and the adjective ‘contemporary’ which means ‘belonging to the present time’.
Therefore, option (b.) is incorrect as these words do not suit the sentence better than option (a.).

Option (c.), ‘retaining, present', refers to the verb ‘retain’ which means ‘allow to remain in a place or position or maintain a property or feature’, and the adjective ‘present’ which means ‘the period of time that is happening now; any continuous stretch of time including the moment of speech’.
Therefore, option (c.) is incorrect as these words do not suit the sentence better than option (a.).

Option (d.), ‘promoting, modern', refers to the verb ‘promote’ which means ‘contribute to the progress or growth of’ and the adjective ‘modern’, which means ‘belonging to the modern era; since the Middle Ages’.
Therefore, option (d.) is incorrect as these words do not suit the sentence better than option (a.).

Option (e.), ‘evolving, self-centered', refers to the verb ‘evolve’ which means ‘undergo development or evolution’, and the adjective ‘self-centered’ which means ‘limited to or caring only about yourself and your own needs’.
Therefore, option (d.) is incorrect as these words do not suit the sentence better than option (a.).

Note:
In this question, the student should notice that many of the options are similar in meaning to each other. Such words are called synonyms. Thus, two words that can be interchanged in a context are said to be synonymous relative to that context.