They asked if I know anything about the Great Barrier Reef.
→ B: "know" should be "knew".
Corrected sentence: They asked if I knew anything about the Great Barrier Reef.

He wanted to know if Mount Everest reaches its highest peak in 1953.
→ C: "reaches" should be "reached".
Corrected sentence: He wanted to know if Mount Everest reached its highest peak in 1953.

They asked if we intended to visit Victoria Falls following year.
→ D: "following year" should be "the following year".
Corrected sentence: They asked if we intended to visit Victoria Falls the following year.

They wanted to know where we liked the lush and vibrant Amazon Rainforest.
→ C: "liked" should be "live" or "enjoyed" (depending on the intended meaning).
Corrected sentence: They wanted to know where we live in the lush and vibrant Amazon Rainforest.
Or: They wanted to know where we enjoyed the lush and vibrant Amazon Rainforest.

She wondered if the Amazon Rainforest will continue to face deforestation.
→ C: "will" should be "would".
Corrected sentence: She wondered if the Amazon Rainforest would continue to face deforestation.