please explain why the answer is c and e for the question number 3 and 4.

thank you.

A. The structure of doxorubicin, a drug widely used in chemotherapy and treatment of cancer. is shown below. Questions 1 to 6 pertain to this structure. 3. The bond between carbons labeled "c" and "d" is formed by overlap of which type of orbitals on these atoms? (a) sp3(C " c") )sp3(C "d") (b) sp2(C "c")-sp 2(C d") (c) sp2(C "c")-sp (C "d") (d) sp3(C "c")-sp" (C "d") 4. How many degrees of unsaturation does doxorubicin have? (Molecular Formula: C27H29NO11 ) (a) 7 (b) 5 (c) 13 (d) 9 (e) 14