Which of the following LED emits red and yellow light?

The semiconductor used for fabrication of visible LEDs must have a band gap of at least $1.8 \text{ eV}$.

Gallium Arsenide Phosphide ($\text{GaAs}_{1-x}\text{P}_x$) is used for making LEDs of different colours such as red, yellow, and orange.

For example, $\text{GaAs}_{0.6}\text{P}_{0.4}$ ($E_g \approx 1.9 \text{ eV}$) is used for red LEDs.

Gallium Arsenide ($\text{GaAs}$) has a band gap of $\approx 1.4 \text{ eV}$ and is used for infrared LEDs.

Gallium Phosphide ($\text{GaP}$) is typically used for green LEDs.

Thus, $\text{Ga}-\text{As}-\text{P}$ is the material that emits red and yellow light.

Answer: $\text{Ga} - \text{As} - \text{P}$