1. A $5000 promissory note payable to order of Ned is discounted to Bob by blank indorsement for $4000. Ken steals the note from Bob and sells it to Olly, who promises to pay Ken $4500. After paying Ken, $3000, Olly learns that Ken stole the note. Olly makes no further payment to Ken. Olly is

Select one or more:

a. Aholder in due course to the extent of $5000.

b. An ordinary holder to the extent of $4500.

c. A holder in due course to the extent of $3,333.

d. A holder in due course to the extent of $4000.

Choice C is the answer, but I'm unsure why. Please provide an explanation with calculations if necessary. This is a commercial law question.