Which of the following statements is/are correct about Buchanan's journals?

a. He was critical of the lifestyles of forest dwellers and felt that forests had to be turned into agricultural lands. b. While recording the lanscape, he always recorded what crops could be cultivated, which trees could be cut down, and which ones could be grown in place of the present vegetation. c. He obsessively observed the stones and rocks, and the different strata and layers of soil.