Option d is the correct answer. Muhammad Bin Tughluq was the ruler who introduced the concept of token currency in India. In 1330, faced with financial constraints after a failed expedition, he issued coins made of brass and copper with a nominal value equal to that of gold and silver coins. This form of currency, known as token currency, aimed to save precious metals like gold and silver and introduce more money in circulation. However, it resulted in a devaluation of coins, disrupted trade, and led to confusion between official and counterfeit coins. The token currency experiment was short-lived and was abandoned by 1333 due to its negative impact on the economy and trade. Important Tips Chronology of events during Muhammad Bin Tugluqh's reign: Conquest of Warangal (1323): Before ascending the throne, Muhammad bin Tughluq successfully laid siege to the Kakatiya capital in Warangal in 1323, marking the end of the Kakatiya dynasty. Accession to the Throne (1325): Muhammad bin Tughluq became the Sultan of Delhi in February 1325 following the death of his father, Ghiyasuddin Tughlaq. Transfer of the Capital to Daulatabad (1327): In 1327, he ordered the capital of the Delhi Sultanate to be moved from Delhi to Daulatabad (also known as Devagiri) in the Deccan region. This decision had significant consequences for the empire. Token Currency Experiment (1330-1333): In 1330, he introduced a token currency made of brass and copper with values equal to gold and silver coins. This move was aimed at addressing financial challenges but resulted in economic disruption and loss of trust in the currency. Expedition to Himachal (1333): In 1333, Muhammad bin Tughluq led an expedition to the Kullu-Kangra region of modern-day Himachal Pradesh but faced resistance from local rulers and ultimately retreated. Return of the Capital to Delhi (1335): Due to various challenges, including revolts and logistical issues, he decided to shift the capital back from Daulatabad to Delhi in 1335. Death (1351): Muhammad bin Tughluq died in 1351 while campaigning in Sindh against the Taghi tribe.