Identify the figure description given in the options which when put in place of '?' will logically complete the given series.

The pattern expands step-by-step by adding one small square at a new corner in a clockwise sequence:
1. Top-Left corner
2. Top-Left $+$ Top-Right corner
3. Top-Left $+$ Top-Right $+$ Bottom-Right corner
4. Following this sequence, the next step adds a small square to the final remaining corner (Bottom-Left corner), resulting in all four corners being occupied.