The question asks about the association of the term "Vaaksukta." Let's analyze each option to identify which Veda it is related to:

1. Rigveda: The Rigveda is one of the oldest and most important Vedic texts, consisting of hymns dedicated to various deities. The "Vaaksukta" refers to a particular hymn or section within the Rigveda that is devoted to the concept of "Vāk" (speech), often personified as a goddess. This hymn is significant because it emphasizes the power and sanctity of speech.
2. Samveda: This Veda is primarily a collection of melodies, and it serves as a book of chants. The hymns in Samveda are meant for musical recitation and are essential for Vedic rituals, but there is no specific association with "Vaaksukta."
3. Yajurveda: This Veda consists of prose mantras used in rituals and sacrifices. It is primarily a guide for priests performing ceremonial duties, with no direct reference to "Vaaksukta."
4. Atharvaveda: Known for its spells, charms, and incantations, the Atharvaveda deals with everyday life topics. Although it covers a broad range of subjects, it does not specifically relate to "Vaaksukta."

Based on the analysis, the correct answer is Rigveda because the "Vaaksukta" is a well-known hymn within this Vedic text, emphasizing the power of speech.

Therefore, the correct option is:

Rigveda