Definition: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Input: Passage: On 7 August 1998, al-Qaeda struck the U.S. embassies in Kenya and Tanzania, killing 224 people, including 12 Americans. In retaliation, U.S. President Bill Clinton launched Operation Infinite Reach, a bombing campaign in Sudan and Afghanistan against targets the U.S. asserted were associated with WIFJAJC, although others have questioned whether a pharmaceutical plant in Sudan was used as a chemical warfare plant. The plant produced much of the region's antimalarial drugs and around 50% of Sudan's pharmaceutical needs. The strikes failed to kill any leaders of WIFJAJC or the Taliban.
Output:
What happened on 8 August 1997?