Respuesta :

tonb
Dividing means you subtract the exponents. Dividing by a number is the same as changing the sign on the exponent. 

x⁰/x² = x⁻² = 1/x²
y⁻³/y⁻¹ = y⁻³⁻⁻¹ = y⁻² = 1/y²

together is 1/x²y², answer B