Final answer:
The spelling error in the sentence should be corrected by changing 'discusing' to 'discussing'.
Step-by-step explanation:
The spelling error in the sentence is in the word 'discusing' which should be changed to 'discussing' to correct the error. 'Discussing' is the correct spelling of the word, which means to have a conversation or talk about a topic. Therefore, option B is the correct choice.
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