Answer:
The correct answer is letter "E": unfreezing.
Explanation:
Based on the organization changing model of German psychologist Kurt Lewin (1890-1947), unfreezing is the step of a company where a change is claimed and introduced to its employees. The firm is said to be "frozen" since it has remained with a single operation method over time and external and internal factors imply the company must change to survive.
In that case, "Meet & Greet" when from having a few engineers using desktop computers to a vast number of professionals using mobile apps, something widely spread in the past five (5) years.