One way to reduce the shortage of food for a growing population would be

The most obvious way to reduce the shortage of food is to reduce population which seems like a long term effort however science has enables us to develop certain ways that could be used to reduce the shortage of food. We are familiar with the term genetically modified plants and animals.  

This technique has enabled us to produce plants and animals of our choice at a faster rate than normal.  

With the help of this we can put desirable traits in organisms.

well, i believe that the answer is 2. : 3