Step 1: Verify Source Information.
The provided text explicitly states the Kisan Credit Card scheme was launched in August 1998 by Indian financial institutions.
Step 2: Discard Inaccurate Selections.
- July 2002: Not supported by the source.
- August 1993: Incorrect; the scheme was not active then.
- June 1998: The month is not accurate.
Step 3: Determine Correct Answer.
Therefore, the accurate introduction date is August 1998.
Final Answer: \[\boxed{\text{Kisan Credit Card scheme was introduced in August 1998.}}\]