The correct answer is D. Enunciativa
Step-by-step explanation:
This question requires you to identify the grammatical mood, this includes imperative or "imperativo" that is used for requests and orders; interrogative or "interrogativo" that is used for questions; the "exclamative" mood that is used for sentences with an emotional charge and can be identified due to the use of exclamation marks (!), and the indicative or "enunciativo" used to state facts or events. According to this, the sentence "Lograron encontrar el fallo en el motor" that means "They managed to find the fail/problem in the engine" is an indicative sentence or "oración enunciative" because it simply reports a fact.