Final answer:
Paytm is definitely a payment processing system, and 'checkout' might refer to Checkout.com, another payment processor, while 'code' is unrelated. Assuming checkout refers to a system like Checkout.com, the correct answer is all of the mentioned.
Step-by-step explanation:
The question is asking which of the following options is a payment processing system. Option (a) Paytm is indeed a payment processing system that allows users to make various transactions, such as paying bills, transferring money, and more.
Option (b) 'checkout' could refer to a generic checkout process in e-commerce or possibly to systems like 'Checkout.com' which is also a payment processing solution. Option (c) 'code' does not specify a payment system; it seems more related to programming and is not typically associated with payment processing. In this context, assuming 'checkout' refers to a payment processing system like Checkout.com, the answer would be (d) all of the mentioned.