Final answer:
Prophylactic probiotics have the greatest effect on lowering the risk of NEC.
Step-by-step explanation:
The intervention that has the greatest effect on lowering the risk of Necrotizing Enterocolitis (NEC) is Prophylactic probiotics. Probiotics are live microorganisms that can confer health benefits when administered in adequate amounts. Several studies have shown that the use of prophylactic probiotics, such as Lactobacillus and Bifidobacterium strains, can significantly reduce the incidence of NEC in premature infants. These probiotics help to establish a healthy gut microbiome and strengthen the immune system, which plays a crucial role in protecting against NEC.