A 16 out of 25 means you got a 64%, which means you got a "D."
A+ = 97 - 100
A = 94 - 96
A- = 90 - 93
B+ = 87 - 89
B = 83 - 86
B- = 80 - 82
C+ = 77 - 79
C = 73 - 76
C- = 70 - 72
D+ = 67 - 69
D = 63 - 66
D- = 60 - 62
E+ = 40 - 59
E = 20 - 39
E- = 0 - 19
