Indian chess Grandmaster Viswanathan Anand won a prestigious Rapid World Chess Championship title by defeating which opponent in the final?

Introduction / Context:
Viswanathan Anand is one of India's greatest sporting icons and a former World Chess Champion. Apart from classical world titles, Anand has also excelled in rapid chess, winning many elite rapid events. This question refers to a Rapid World Chess Championship where Anand defeated a top level grandmaster in the final. Knowing this fact helps you connect Indian sports achievements with specific international events, which is a common pattern in general knowledge examinations.

Given Data / Assumptions:

• The player in focus is Indian Grandmaster Viswanathan Anand.
• The event is a Rapid World Chess Championship level event.
• The question asks for the opponent Anand defeated in the final.
• The options list several legendary grandmasters from different countries.

Concept / Approach:
The main concept here is factual recall. Anand has played many famous rivals, but not all of them have been his opponents in rapid world championship finals. In this context, Levon Aronian, an Armenian grandmaster, is the correct opponent associated with Anand's victory in a rapid world championship event. The other names listed are legendary players, but their peak competitive eras were earlier, and they are not linked to this specific rapid final against Anand.

Step-by-Step Solution:
Step 1: Recognise that the question refers to a rapid chess world title linked to Anand's career. Step 2: Recall that in high level rapid chess events in the mid and late 2000s, a famous final was Anand versus Levon Aronian, which Anand won. Step 3: Note that Anatoly Karpov, Robert Fischer, and Boris Spassky belong primarily to an earlier generation of world champions and candidates. Step 4: Compare the options and identify Levon Aronian as the contemporary elite player who actually faced Anand in a rapid championship final. Step 5: Select “Levon Aronian” as the correct answer.

Verification / Alternative check:
You can verify by thinking about chess history timelines. Fischer and Spassky played their famous world championship match in 1972, which is long before Anand's peak. Karpov dominated the 1970s and 1980s. By the time rapid events featuring Anand became prominent, Levon Aronian had become one of the strongest contemporary grandmasters. Various chess resources and tournament reports on rapid championships confirm that Anand defeated Aronian in the final of a major rapid championship, supporting this answer choice.

Why Other Options Are Wrong:
Anatoly Karpov: A former world champion from an earlier generation, not Anand's opponent in the noted rapid world championship final.
Robert Fischer: The American legend and world champion from 1972 to 1975, not active at the time of Anand's rapid world titles.
Boris Spassky: Another earlier world champion and Fischer's rival, not paired with Anand in a rapid world championship final.
Vladimir Kramnik: A strong world champion and Anand's rival in classical chess, but the famous rapid world championship win referred to in this question is associated with Levon Aronian, not Kramnik.

Common Pitfalls:
A common error is to associate Anand with any famous world champion without carefully linking the event type and era. Students may incorrectly choose Karpov or Kramnik simply because they know those names are big in chess history. To avoid such mistakes, always align the timeline of players and the specific format of the event, such as rapid, blitz, or classical, before making your choice.

Final Answer:
Viswanathan Anand won the Rapid World Chess Championship by defeating Levon Aronian in the final.