In each of the questions given below, a sentence is given with some bold words which may contain errors. Below each sentence, a table is given with two columns in which column 'A' contains the list of bold words, and in column 'B' the suggested corrections are listed. You have to choose the best alternative among the four given option. If no correction is required against the given options, mark (5), i.e 'No Improvement' as your answer.  

Consider a (1) complex real-world problem, like those of marketing or making (2) pensive for a nation, where there are many (3) governing factors and most of them cannot be expressed as (4) numerical time series data, as one would like to have for building mathematical models.

Column A                              Column B 

1. Complex                            5. Simple

2. Pensive                             6. Policies

3. Governing                         7. government

4. Numerical                          8. Conditional