Which grammatical issue is found in the phrase "many 19th-century people the sewing machine was probably as awe-inspiring"?

The phrase "many 19th-century people the sewing machine was probably as awe-inspiring" contains a grammatical issue that stems from missing punctuation. In this context, the phrase lacks necessary punctuation to separate the subject ("many 19th-century people") from the verb and the rest of the sentence. Including proper punctuation, such as a comma or restructuring the sentence, would help clarify the relationship between the different parts of the sentence and ensure that it conveys a complete thought.

Other options may stem from various grammatical issues, but they do not accurately reflect the problem at hand. The phrase is not a complete sentence on its own due to the absence of breaks, which are crucial for reader understanding.