Is the group of words a simple sentence, a compound sentence, or a run-on sentence? the ledge was narrow, but one person could stand on it. a. run-on sentence b. simple sentence c. compound sentence i have no idea what this one is

The sentence "The ledge was narrow, but one person could stand on it." Is C: A compound sentence.
Compound sentences are sentences that are made up of two or more phrases that could be complete sentences on their own, but are put together to make it less choppy and easier to read.
A good way to easily spot a compound sentence is conjunctions. Conjunctions are words like "and," "but," or "or."
These words are used to put together phrases that could otherwise stand alone.
For example, in the sentence "The ledge was narrow, but one person could stand on it." There are two phrases that could be their own sentences.
"The ledge was narrow."
And
"One person could stand on it."
These two are joined together by the word "but" to make it flow better, thus making it a compound sentence.
Therefore, the answer is C: a compound sentence.