Question

Each question consists of a set of numbered statements. Assume that each one of these statements is individually true. Each of the four choices consists of a subset of these statements. Choose the subset as your answer where the statements therein are logically consistent among themselves.
A. Only if the water level in the coastal areas rises, do the people change their lifestyle.
B. People change their lifestyle only if they are rewarded.
C. If people are rewarded, then they will not change their lifestyle.
D. If the temperature rises, then the water level in the coastal areas rises.
E. Whenever the water level in the coastal area rises, the temperature rises.
F. Unless the people change their lifestyle, temperature rises.
G. People are rewarded.
H. Water level in the coastal areas does not rise.

• A. C, D, F, G and H
• B. G, F, D, B and H
• C. E, F, G, H and B
• D. None of the above

Hint:

Turn each sentence into an if-then rule, fix the facts first (which statement is rewarded / which is not risen), then chain forward and look for a rule that is forced into two different values.

Answer 1

The Correct Option is C

Translate every statement into an if-then rule first, using c = people change lifestyle, r = rewarded, t = temperature rises, w = water level rises. A: c → w. B: c → r. C: r → not c. D: t → w. E: w → t. F: not c → t. G: r is true. H: w is false. Now test each option by starting from the facts (G, H) and chaining forward through the rules included in that option.

1. Option A (C, D, F, G, H): G gives r = true. Rule C then forces not c, so c = false. With c false, rule F (not c → t) forces t = true. Rule D (t → w) then forces w = true. But H directly says w is false. That is a straight contradiction (w cannot be both true and false), so this subset cannot all be true together.
2. Option B (G, F, D, B, H): G gives r = true, and B (c → r) is automatically satisfied whether c is true or false, so c is left undecided by this subset; F only tells us what happens if c is false, D only tells us what happens if t is true, so the chain never actually reaches a value for t or w on its own, and H's fact about w is simply asserted without the rest of the subset being able to confirm or contradict it directly through forward reasoning. This subset does not hang together as one connected, verifiable chain.
3. Option C (E, F, G, H and B): G gives r = true. H gives w = false, so rule E (w → t), whose condition w is false, does not force t either way, so it does not create any conflict. F only fires if c is false, which is not asserted here. B (c → r) is satisfied regardless of c, since r is already true. Every rule in this subset is either satisfied outright or simply not triggered, so nothing in the set clashes with anything else.

Only option C's rules can all hold together without any rule forcing a value that contradicts another rule in the same subset.

So the correct answer is option C, E, F, G, H and B.