The answer to your question would be that the answer choice that shows the best way to introduce a sentence that summarizes or explains the information before it is the following one: Marissa wil be a huge help: she is going to organize the children to spread the soil in the new gardens.
The colon is the best choice because the second sentence explains, illustrates, and expands on the first sentence. The first sentence states that Marissa will be huge help and the second one the reason why she is considered a huge help.
Answer:
Marissa will be a huge help: she is going to organize the children to spread the soil in the new gardens.
Explanation:
