In classical Carnatic music, tempo is called as ________.

The correct answer is laya.

In classical Carnatic music, as well as in Hindustani classical music, the term used to denote tempo or rhythm speed is laya. It refers to the speed or pace at which a musical composition or rhythmic cycle (tala) is performed.

Let us briefly look at the terms provided in the options:

1. Laya: Represents the tempo, rhythm, or speed of music.
2. Padam: A musical form or composition in Carnatic music, usually of a sensitive or devotional nature used in dance.
3. Gita: A simple form of musical composition taught to beginners in Carnatic music.
4. Achala: Refers to fixed or unchangeable notes (swaras like Shadja and Panchama) in Indian classical music.

Therefore, tempo in classical Carnatic music is known as laya.