The correct option is D transient
Eternal means lasting or existing forever. The opposite of eternal is transient, or lasting only for a short time; impermanent. Hence, Option D is correct. Among the rest of the options, immaterial means unimportant under the circumstances; irrelevant, divine means related to a god or a higher being, spiritual means relating to or affecting the human spirit or soul as opposed to material or physical things. These options do not express the intended antonym, hence incorrect.