Lenticels are lens shaped opening permitting exchange of gases between the outer atmosphere and internal tissue of the stem. Bark that is formed early in the season is called early or soft bark. Towards the end of the season late or hard bark is formed. Bark is non-technical term that refer to all tissues exterior to vascular cambium. Bark refers to a number of tissue types, viz periderm and secondary phloem. Phellogen is couple of layers thick Therefore, only statement A and D are correct.