It took >30 minutes for me to prepare the mathematical model and to understand the logic; pretty useless for GMAT exam. Nevertheless, here is:
Argument:
1. Tax(A) -> -Profit(A) OR (inclusive) +Price(A)
2. +Price(A) -> -Demand(A) AND +Demand(A-sub)
3. +Demand(X) -> +Price(X)
Now, as per logic,
(i) if a statement is true, its Contrapositive is also true.
P -> Q => ~Q -> ~P
here ~ means negation (logical opposite)
(ii) negation rules
~ (A OR B) => ~A AND ~B
Key note: negation of: Demand UP is NOT Demand DOWN. It is ! (Demand UP) => Demand SAME OR DOWN.
Now let's look at arguments again followed by all options:
Given:
1. Tax(A) -> -Profit(A) OR (inclusive) +Price(A)
2. +Price(A) -> -Demand(A) AND +Demand(A-sub)
3. +Demand(X) -> +Price(X)
(A) Tax(A) AND +Price(A-sub) . => -Profit(A)
We cannot logically deduce from above. In fact, +Price(A-sub) does not convey anything.
(B) Tax(A) AND ~(+Price(A-sub)) => -Profit(A)
from (3), ~(+Price(A-sub)) => ~(+Demand(A-sub))
from (2), ~(-Demand(A)) OR ~(+Demand(A-sub)) => ~Price(A)
from (1) => Tax(A) AND ~Price(A) => -Profit(A)
(C) -Price(A-sub) AND +Demand(A) => Repealed Tax(A)
Repealed, to me, is not clear here.
Does it mean: Repealed Tax(A) = ~(Tax(A)) OR Repealed Tax(A) = !(Tax(A)).
(D) Tax(A) AND +Demand(A-sub) => +Price(A)
+Demand(A-sub) => +Price(A-sub)
Now, we cannot make a jump:
+Price(A-sub) =>...=> +Price(A)
(E) +Demand(A-sub) AND -Profit(A) => Tax(A)
again:
+Demand(A-sub) => +Price(A-sub) ...stuck..can't deduce further
combining with (1)
Tax(A) -> -Profit(A) OR (inclusive) +Price(A)
Given: -Profit(A) . ===DOES NOT ===> Tax(A)