If the Tax Function Is T = T₀ + T₁Y

If the tax function is T = t₀ + t₁Y where t₁ equals 1/3,and if the marginal propensity to consume out of disposable income is 3/4,then the change in GDP per unit change in t₀ (ΔY/Δt₀) will be

A) − 1.
B) + 1.
C) − 1.5.
D) − 2.
E) + 1.5.