The table below shows the market shares of firms in the domestic commercial aviation industry of Country Y in 2021 and 2024.
| Firm | 2021 Market Share (%) | 2024 Market Share (%) |
|---|---|---|
| Apex Air | 35 | 31 |
| Blue Sky | 22 | 26 |
| Cardinal Fly | 18 | 20 |
| Dawn Aviation | 11 | 14 |
| Horizon | 9 | 6 |
| Others | 5 | 3 |
Which of the following correctly identifies the change in the three-firm concentration ratio (CR3CR_3CR3) from 2021 to 2024, and the market structure of this industry in 2024?
An increase of 2 percentage points; oligopolistic
A decrease of 4 percentage points; monopolistically competitive
An increase of 5 percentage points; oligopolistic
An increase of 2 percentage points; perfectly competitive
