Product Type ordered after one order type is placed

Currently, my Data set is as follows:

A Customer can place various orders of Product types: A, B, C, D on multiple dates. 

My client wants to know which is the product type order placed by the customer after he has placed order type C and how many days after he placed the next product type order after Order Type C.

Also, Products can be placed multiple times over the course of multiple years. So for this problem, the client wants to know the first time when the order type C was placed and the subsequent order type placed and after how many days.

THANK YOU