Answer:
7 octaves
Explanation:
Total number of keys in piano = 88 keys
Numbers of keys in each group called octave= 12 unique keys
We have to find the number of complete octaves on piano
Number of octaves consists of 12 keys=

Number of octaves consists of 12 keys=

Number of octaves consists of 12 keys= 7 octaves
Hence, the correct answer is 7 octaves