The most common way to form the plural of a noun is to add -s. The correct answer is option A. Adding -s is the most common, but is not generally applicable to all nouns. Other nouns need to be added with -es in order to form the plural noun such as the word "box". The plural form of the word box is boxes.
To overcome the feeling of sadness and the birth of nature hope this helps
I would say that it's a mixture of both a and c, but I would go with C because a could go for a fact.
