Form the plural form of the noun.

 calf. 

• The plural form of a noun ending in -f or -fe is generated by deleting the -f or -fe and replacing it with -ves.
• For example, the plural form of a leaf is leaves.
• For the above given singular form of a noun ending with 'f' to make the plural form of the given word, we need to delete the 'f' word and add the 'ves'
•  Calves are the plural version of the word calf.
• Option A is the right response.
• The words calvs, calfs, and calfes have incorrect spellings.
•  Therefore, A, B and C are the incorrect answers.

Hence option A is the correct answer.