Convert the following equation into sum of product (sop) form : R = L + M'(N'M + M'L)

Expanding $R = L + M'(N'M + M'L)$ using Boolean identities gives $R = L + M'N'M + M'M'L = L + 0 + M'L = L$. Expressing $L$ as a sum of products over $M$ and $L$ gives $L(M + M') = ML + M'L$. Among the other options, $(M + L)(M' + L)$ is in product-of-sums form, while $M'L' + ML$ and $L + M'N$ are not logically equivalent to $L$.