| List -I | List-II | ||
| A | Aspergillus niger | I | Butyric acid |
| B | Clostridium butylicum | II | Acetic acid |
| C | Saccharomyces cervisiae | III | Citric acid |
| D | Acetobacter aceti | IV | Ethanol |


Rearrange the following parts to form a meaningful and grammatically correct sentence:
P. that maintaining a positive attitude
Q. even in difficult situations
R. is essential for success
S. and helps overcome obstacles effectively