That "box" may be a printer for the computer in the desk or a compartment for tissues / beverages
If it’s like the one in C then it is cabinet with an opening for a printer and I think two compartments.
.@BBCCarrie had one of the toughest journalism assignments at the BBC: China Editor. She says they "begged" her to take the job. Finally she agreed. Then she found out she was being paid less than half the salary of some of her male colleagues - and her fight for equal pay began. pic.twitter.com/c8vmykkly5— Christiane Amanpour (@camanpour) September 11, 2019