Final answer:
Option 1: A student struggling to understand a lecture in a foreign language class.
Step-by-step explanation:
The scenario that demonstrates the existence of a language barrier is Option 1: A student struggling to understand a lecture in a foreign language class.
In this scenario, the student is facing difficulty understanding the lecture due to the language barrier. This can happen when the student is not fluent in the foreign language being taught or doesn't have a strong grasp of the vocabulary and grammar used in that language. The language barrier hinders effective communication and understanding between the student and the teacher.