Microbe responsible for converting milk to curd is:

Lactobacillus

The correct answer is Option (2) → Lactobacillus

Lactic Acid Bacteria (LAB) is the term used to describe a group of microorganisms that produce lactic acid as a byproduct of their metabolism. Lactobacillus is a type of LAB that is widely used in various applications, including the production of fermented foods like curd (yogurt) from milk. These bacteria play a crucial role in the fermentation process by converting lactose (milk sugar) into lactic acid, which imparts the characteristic tangy flavor and texture to fermented dairy products.

In summary, microorganisms such as Lactobacillus are commonly referred to as Lactic Acid Bacteria (LAB) due to their ability to produce lactic acid.