Hi you van help me plisss

Which of the following is a complex sentence? a. after henry submitted his essay, he realized that he hadn't proofread the last page. b. identity theft is a growing problem, especially among seniors. c. we didn't have enough potatoes for dinner, so we served rice instead. d. jim tried to watch a video on a device connected to a crowded wireless network; as a result, the video stuttered and froze.

2read this passage from "the raven." what is puzzling the speaker in this stanza? 60% but the raven still beguiling my sad fancy into smiling, straight i wheeled a cushioned seat in front of bird, and bust and door then, upon the velvet sinking, i betook myself to linking fancy unto fancy, thinking what this ominous bird of yore- what this grim, ungainly, ghastly, gaunt and ominous bird of yore meant in croaking "nevermore." s and what the raven's message is why the raven came to visit where the raven came from how the raven got into his room

This is a set of words that begins with a preposition.