Milk curdles when lemon juice is added. This is :
Curds are a dairy product obtained by coagulating milk in a process called curdling. The coagulation can be caused by adding enzymes rennet or any edible acidic substance such as lemon juice or vinegar, and then allowing it to coagulate. Milk curdles when lemon juice is added. This process is called Coagulation.
Option (B) is correct.