We can solve this question using matching operations

Given:
Quantity A: The average (arithmetic mean) of x and y
Quantity B: y - 1

Apply definition of average to get:
Quantity A: (x + y)/2
Quantity B: y - 1

Multiply both quantities by 2 to get:
Quantity A: x + y
Quantity B: 2y - 2

Subtract y from both quantities to get:
Quantity A: x
Quantity B: y - 2

Since it is GIVEN that x < y - 2, we can see that Quantity B is greater.

Answer: B


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