Whom does Valluvar refer to as blocks in the rural

"Arampolum koormaiyar renu amrampolvar"

("Though sharp their wit as a file, as blocks, they must remain..")

The correct answer is Those who do not have love in their hearts.

Key Points

Thiruvalluvar: 

• Commonly known as Valluvar, was a celebrated Tamil poet and philosopher.
• He is best known as the author of the Tirukkuṟaḷ, a collection of couplets on ethics, political and economical matters, and love. The text is considered an exceptional and widely cherished work of Tamil literature.
• Almost no authentic information is available about Valluvar, states Kamil Zvelebil – a scholar of Tamil literature. 
• His life and likely background are variously inferred from his literary works by different biographers.
• There are unauthentic hagiographic and legendary accounts of Valluvar's life, and all major Indian religions, as well as Christian missionaries of the 19th century, have tried to claim him as secretly inspired or originally belonging to their tradition. 
• Little is known with certainty about his family background, religious affiliation, or birthplace.
• He is believed to have lived at least in the town of Mylapore (a neighbourhood of the present-day Chennai), and his floruit is dated variously from 4th century BCE to early 5th century CE, based on the traditional accounts and the linguistic analyses of his writings. 
• Maraimalai Adigal gives 31 BCE as the birth year of Valluvar, while Kamil Zvelebil infers the Tirukkuṟaḷ and Valluvar are best dated to around 500 CE.
• Valluvar refers to as blocks in the rural "Arampolum koormaiyar Renu amrampolvar" ("Though sharp their wit as a file, as blocks they must remain..") Those who do not have love in their hearts. Hence, Option 3 is correct.
• Valluvar has influenced a wide range of scholars down the ages since his time across the ethical, social, political, economic, religious, philosophical, and spiritual spheres. He has long been venerated as a great sage, and his literary works a classic of Tamil culture.
• A person who does not have the characteristic of a person is as sharp-witted as Aram but like a one-eyed tree.
• Those who are not human are as intelligent as Aram but like a tree of knowledge.
• Despite being a sharp-witted genius like Aram, the one who lacks the character of the people is like a tree.
• Though sharp their wit as a file, as blocks they must remain, Whose souls are void of courtesy humane.