Most radiosensitive among the following is

(D) Nucleosomal DNA > Among the factors contributing to the distribution of DNA damage within irradiated mammalian cell nuclei are the interactions of DNA with nuclear proteins and the formation of multi-molecular chromatin structures. Studies on the manipulation of chromatin structures of isolated nuclei are summarised.> The majority of chromatin within the nucleus of living cells is tightly compacted into nucleosomal superhelices and other higher order structures which have a limited ability to be damaged by radiation.> The treatment of isolated nuclei with hypotonic buffers causes a decondensation of these structures and markedly sensitises the DNA to radiation, while retaining the majority of the chromosomal proteins