Final answer:
Spanish-speaking English learners may struggle with the phonemes /θ/ and /d/ in the word "thud", due to the absence of /θ/ in Spanish and the differing pronunciation of /d/ in their native language. Therefore, the correct option is D.
Step-by-step explanation:
The phonemes that a Spanish-speaking English Learner (EL) might have difficulty with in the word "thud" are /θ/ and /d/. The correct answer is D. /th/ and /d/. The /θ/ sound does not exist in Spanish, making it challenging for Spanish speakers to produce this sound that appears in words like "think" and "theatre."
Additionally, while the /d/ sound exists in Spanish, the pronunciation is different, often being less forceful and more dental (tongue against the teeth) than in English, which could lead to difficulty in clearly articulating the /d/ sound as heard in English words.