**Core Concept:** Pulses are a type of food that includes legumes such as lentils, chickpeas, and beans. They are an important source of nutrients for human consumption. Amino acids are building blocks of proteins in the body and are essential for various physiological processes.

**Why the Correct Answer is Right:**

Amino acids are organic compounds containing an amino group (-NH2) and a carboxyl group (-COOH) attached to a carbon backbone. Methionine is an essential amino acid, which means it cannot be synthesized by the human body and must be obtained from the diet, particularly from animal products. In contrast, pulses contain a limited amount of methionine, but they are rich in other essential amino acids such as lysine, threonine, and tryptophan.

**Why Each Wrong Option is Incorrect:**

A. Arginine: This essential amino acid is abundant in pulses, not deficient.
B. Tyrosine: Another essential amino acid present in pulses.
C. Alanine: A non-essential amino acid, meaning the body can synthesize it, and is not deficient in pulses.
D. Methionine: This essential amino acid is deficient in pulses, as explained above.

**Clinical Pearl:** A balanced diet that includes pulses along with animal products can help meet the dietary requirements for all essential amino acids, ensuring proper protein synthesis and overall health.

**Correct Answer:** D. Methionine