Concept:
South Indian classical (Carnatic) music history highlights elite historical composer-lyricists known as Vaggayakaras. The three most celebrated figures are collectively revered as the "Trinity of Carnatic Music" (Trimurti) due to their foundational contributions to devotional and technical song structures.
Step 1: Identify the canonical Carnatic composers from the options.
Let us check the historical background of the listed names:
• A. Shyama Shastri (1762–1827): The oldest of the iconic Trinity, renowned for creating complex rhythmic patterns and beautiful melodies in praise of the Goddess Kamakshi.
• C. Tyagraj (Saint Tyagaraja, 1767–1847): The most prolific composer of the Trinity, who composed thousands of devotional *Kritis* dedicated to Lord Rama that form the core of the Carnatic concert repertoire.
Step 2: Isolate the correct option combination.
As items A and C represent two of the definitive pillars of Carnatic composition, the pair "A and C Only" is the correct choice, corresponding to option (3).