Which sentence has a formal tone

The correct answer is option D) Scientists have spent years trying to determine how tsunamis can be predicted with greater accuracy.

Explanation:

A formal sentence is devoid of any slang, informal sentence structure, abbreviations or mixed language words.

In the above sentence, proper English vocabulary is used in the sentence. There is no slang words in it. Words are not written in their short forms and neither is any street language used. The sentence is structured in a very professional way and none of the words are misspelled.

there is not such an "uncle" in the poem "a servant to servants". the narrator refers to many characters -particularly her brother and her husband- both suffering from mental illness. the woman is also suffering because she does something to but she is not happy with the situation.

the poem has a dramatic monologue about the woman life's circumstances and her traumatic events form the past.

"a servant to servants" is a poem written by robert frost, and is part of a collection of poems "north of boston", of 1915.