Concatenate variable number of lines within a column

Hi,
I would like your help with the following issue

I have many questions in a column (column c) and each question is in several lines, there is not an exact number of lines, some times a question can occupy 2 lines and some others 10 or more lines,
I want to concatenate the different lines of each question within a single line . I also have a number (100) in colum B, these number are in the exact same line as the beginning of each question, maybe I can use these numbers as delimiters for the concatenate formula. In the excel file there is an example of what I have and what I want
Thank you very much for your help

Fernando