Hint: A monument is defined as a structure which is built in memory or honour of a person. It is also built in order to maintain the relevance of a group or community due to their cultural heritage., artistic or historical value.
Complete answer: Samadhis, Graves,Veergala are all monuments which are constructed in memory of a person or an event. Samadhi is the Hindi name for a temple, shrine or a commerator built in order to honour the dead. It is like a mausoleum or a tomb. Samadhis may contain the dead body or might not. Graves are burial monuments that are used to mark the deceased The headstones are made up of granite. Veergala or Veerrgal is a memorial stone which is built to commemorate the sacrifice of a soldier who died in a battle. It is a monument. The word had been taken from the Kannada language ‘Veerakallu’. ‘Veerakallu’ means a Hero’s stone or a warrior stone. Between the 5th and 13th century these warrior stones were built. They were built in memory of the family or local villagers of the dead soldier.
Hence, Option D is the right answer.
Note: Monuments were also constructed for religious purposes. A monument can be listed in the UNESCO World Heritage site if there is a public interest in its preservation. Monuments have been built for thousands of years. They are very durable and can stand for more than thousands of years. They are very important historical sources.