Read the sentence carefully and select the most appropriate option to substitute the underlined part.
Greta Thunberg’s tirade against environmental degeneration shocked the world leaders.

The correct answer is long and angry speech.

Explanation:

The underlined word is tirade.

A tirade is defined as a long, angry, or accusing speech or piece of writing directed at someone or something.

Let's analyze the given options to find the most appropriate substitution:

1. debatable account: Refers to a report or narrative that can be questioned or argued about, which does not capture the intense anger or speech format of a tirade.

2. minute observation: Means a detailed or meticulous watching/examination, which is completely different in meaning.

3. long and angry speech: This perfectly matches the definition of a tirade.

4. innate liberal opinion: Refers to an inborn or natural political/philosophical viewpoint, which is unrelated to a speech or outburst.

Therefore, substituting the underlined word with "long and angry speech" gives the sentence its accurate meaning:

"Greta Thunberg’s long and angry speech against environmental degeneration shocked the world leaders."