7-21D6 B
 What number will a ship station use to identify itself using SITOR (NBDP)?
A. Four-digit SELCAL.
B. Five-digit SELCAL or 9-digit SELCAL number identical to MMSI.
C. 9-digit Inmarsat-F77 I. D. number.
D. 9-digit Inmarsat-FBB I.D. number.
