In English grammar, adjectives may appear in comparative and superlative forms depending on the relationship established between nouns. Understanding the distinction between these structures is essential for accurate interpretation and production of academic and professional texts. Read the sentences below carefully.
I.The new research method is more efficient than the previous one used by the laboratory team.
II.Sarah presented the most detailed report during the international scientific conference.
III.The second proposal appeared cheaper than the original financial plan discussed yesterday.
IV.This is the most challenging project developed by the engineering department this year.
V.The blue vehicle seems faster than the transportation model acquired last semester.

Based on the sentences above, analyze the following statements.
(   ) Sentences I, III, and V contain adjectives in the comparative form.
(   ) Sentences II and IV contain adjectives in the superlative form.
(   ) The adjective structure "more efficient than" expresses a comparison between two elements.
(   ) The expression "the most challenging" indicates the lowest degree of comparison.

Choose the correct alternative: