Teacher: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Teacher: Now, understand the problem? If you are still confused, see the following example:
what is the first event mentioned?, Context: The Russian Revolution is the series of revolutions in Russia in 1917, which destroyed the Tsarist autocracy and led to the creation of the Soviet Union. Following the abdication of Nicholas II of Russia, the Russian Provisional Government was established. In October 1917, a red faction revolution occurred in which the Red Guard, armed groups of workers and deserting soldiers directed by the Bolshevik Party, seized control of Saint Petersburg (then known as Petrograd) and began an immediate armed takeover of cities and villages throughout the former Russian Empire.
Solution: Russian Revolution
Reason: This is a good example, and the Russian Revolution is the first event mentioned.

Now, solve this instance: Dialects are versions of a?, Context: The most common, and most purely linguistic, criterion is that of mutual intelligibility: two varieties are said to be dialects of the same language if being a speaker of one variety confers sufficient knowledge to understand and be understood by a speaker of the other; otherwise, they are said to be different languages. However, this definition becomes problematic in the case of dialect continua, in which it may be the case that dialect B is mutually intelligible with both dialect A and dialect C but dialects A and C are not mutually intelligible with each other. In this case the criterion of mutual intelligibility makes it impossible to decide whether A and C are dialects of the same language or not. Cases may also arise in which a speaker of dialect X can understand a speaker of dialect Y, but not vice versa; the mutual intelligibility criterion flounders here as well.
Student:
language