The correct option is D 4, 2, 3, 1
According to Charles Darwin the correct sequence of events in the origin of species are struggle for existence, variation and their inheritance, survival of the fittest and natural selection.
There is struggle for existence, because of the disparity between the number of individuals produced by reproduction and the number that can survive.
Individuals within a species shows variations as no two individuals are same.
Those who have advantageous characters, have a greater probability of survival, and thus fittest organism survives. These are selected by the nature and weaker ones, gets eliminated.
So, the correct answer is option 'd'.