Correct option is D
Dictation.
Dictation is a teaching technique where the teacher reads a passage aloud, and the students write it down. This method helps in improving spelling because it requires students to listen carefully and transcribe the words correctly. It connects the auditory perception of the word to its written form, reinforcing the correct spelling in the student's mind. Additionally, regular practice of dictation can enhance students' listening, writing, and concentration skills. While other options like pronunciation drill and loud reading might indirectly help, dictation directly addresses the issue of spelling mistakes.