Poorly worded question. You could use the COMMA informat to read "FRED". The result would be a missing value.
I suspect they want you to answer A as it will read all of those strings as numbers.
But the value it gets for the last one is wrong. The string 18% means the number 0.18 and the COMMA informat will read it as 18 instead.
data test;
input id $ value comma12.;
cards;
B. $177.95
C. 12,805
D. 18 %
;
proc print;
run;
Obs id value
1 B. 177.95
2 C. 12805.00
3 D. 18.00