What is Adele’s effort described as?

The choice indicating that Adele's effort is described as frustrating suggests that despite her intentions or hard work, she faced significant obstacles or difficulties that hindered her progress or outcomes. This implies a narrative where challenges outweigh the positive aspects of her efforts. The emotional connotation of "frustrating" evokes a sense of struggle and perhaps disappointment, which can resonate strongly, especially in contexts of personal or artistic endeavor where success isn't always guaranteed, regardless of effort.

In contrast, the other options evoke a more positive or neutral assessment. The term "effective" denotes a successful outcome or a positive impact, while "successful" directly indicates that her efforts were fruitful. "Achieving" implies that she reached a goal but doesn’t carry the same emotional weight as "frustrating." Therefore, in the context of the question, "frustrating" captures the essence of a challenging experience more accurately than the alternatives presented.