Final answer:
Barter transactions are not currently allowed in the Indian financial markets. Other options such as algorithmic trading, options trading, and short selling are permitted and regulated by SEBI. Barter transactions are impractical due to their inability to fit into the modern financial regulatory framework. Therefore, the correct option is D.
Step-by-step explanation:
In the context of financial markets in India, among the options provided, the one that is not currently allowed is d) Barter transactions. Algorithmic trading, options trading, and short selling are all permitted within the regulatory framework set by the Securities and Exchange Board of India (SEBI). Barter transactions, however, are not a standard practice in financial markets because they do not involve monetary currency exchange and therefore cannot be easily regulated or taxed in the same way as other forms of trading.
Barter systems are less common in modern economies due to complications such as double coincidence of wants, lack of divisibility, difficulties in storing value, and the inability to enter future contracts effectively, as in the case of perishable goods like strawberries for a tractor purchase.