The poor business model is ------ caused the software developer to go bankrupt.
a. what b. who c. that d. which
Isis Biomedical claims ----- an effective cure for a major disease.
a. to have discovered b. to discover c. will discover d. discovered
I appreciate your ------ our organically-grown fruit and vegetables.
a. ordered b. having ordered c. order d. orders
Selling the product will become ------ when the advertising campaign ends.
a. challenge b. challenged c. challenging d. to challenge