May be lacking in the diet of strict vegetarians (vegans).

Okay listen up people! I am vegan and if you go vegan, you will not lack anything! Most people believe that going vegan means you will be lacking in protein because of not eating meat but that's not true. Many plants like avacadoes, beans, chickpeas, etc are very healthy sources of protein. Meat has protein in itself but it deteriorates the body. On the other hand, plant-based proteins are much healthier. So in other words, nothing is lacking when you go vegan and the benefits are priceless!

i think the answer is d.