Correct answer: A. Britain gave a clear warning against German expansion
Explanation: Direct answer: Option A is correct. The British guarantee to Poland, announced in 1939, meant that Britain publicly promised to support Poland if its independence was attacked, especially by Germany. It represented a stronger stand against further German expansion after the earlier policy of appeasement had failed to stop Hitler. Step by step: Germany expanded into neighbouring territories; appeasement did not prevent aggression; Britain then gave Poland a guarantee; after Germany invaded Poland in September 1939, Britain and France declared war on Germany. Option A is correct because it expresses a clear warning and deterrent against German expansion. Option B is wrong because Britain was not forming an alliance with Germany. Option C is wrong because the guarantee was intended to defend Poland, not abandon it, although military support could not immediately save Poland. Option D is wrong because Britain did not give Poland to Japan; Japan was not the party receiving Poland. Exam cue: Poland guarantee means a shift from appeasement to a firmer anti-expansion policy.