Explanation:

To determine the key located to the immediate left of a group of two black keys on the piano, we need to understand the layout of the piano keyboard.

Piano Keyboard Layout:
- The piano keyboard consists of white and black keys arranged in a repeating pattern.
- The black keys are grouped in sets of two and sets of three.
- The white keys are labeled with letters representing musical notes from A to G.

Identifying the Key:
1. Locate a group of two black keys on the piano keyboard.
2. The key to the immediate left of this group of two black keys is a white key.
3. To determine the name of this white key, we need to consider the musical notes represented by the black keys.

Using the Musical Alphabet:
1. The musical alphabet consists of the letters A to G which represent the different musical notes.
2. The black keys on the piano represent the sharps (#) or flats (♭) of the adjacent white keys.
3. The black key to the immediate left of a white key indicates that the white key is a flat (♭) of the corresponding musical note.
4. In this case, the black key to the immediate left of the white key we are trying to identify is the black key between C and D.
5. Therefore, the white key to the immediate left of this group of two black keys is the flat (♭) of C.
6. The musical note before C is B, and when we flatten B, it becomes B♭.
7. Hence, the key located to the immediate left of a group of two black keys is B♭.

Correct Answer:
The correct answer is option 'B' - B♭.