To solve this problem, we need to analyze each statement and determine which are correct:$\newline \bullet$(a) Euchromatin is loosely packed chromatin:$\newline$ - Euchromatin is indeed loosely packed and is generally transcriptionally active.$\newline$ - Therefore, statement (a) is correct.$\newline \bullet$(b) Heterochromatin is transcriptionally active:$\newline$ - Heterochromatin is tightly packed and is usually transcriptionally inactive.$\newline$ - Therefore, statement (b) is incorrect.$\newline \bullet$(c) Histone octamer is wrapped by negatively charged DNA in nucleosome:$\newline$ - DNA is negatively charged due to its phosphate backbone and wraps around the positively charged histone octamer.$\newline$ - Therefore, statement (c) is correct.$\newline \bullet$(d) Histones are rich in lysine and arginine:$\newline$ - Histones are proteins that are rich in the basic amino acids lysine and arginine, which help them bind to the negatively charged DNA.$\newline$ - Therefore, statement (d) is correct.$\newline \bullet$(e) A typical nucleosome contains 400 bp of DNA helix:$\newline$ - A typical nucleosome contains about 146 base pairs of DNA wrapped around the histone octamer.$\newline$ - Therefore, statement (e) is incorrect.$\newline$Now, let's identify the correct set of statements:$\newline$The correct statements are (a), (c), and (d).$\newline$This corresponds to Option 2: (a), (c), (d) Only.