Theres no misspelled word in that sentence
The correct answer is B: HOWEVER.
From the passage given above, it can be seen that the similarities between coal and petroleum is the principal subject of the passage. The author gives several points that are jointly shared by both coal and petroleum. The author only gives one contrast between the two and in the process of making the contrast, he used the word 'HOWEVER'. The difference that the author gives about coal and petroleum is in their formation.
