Answer:
the sentences with correct verb agreements are:
a. ) many small retailers working out of a single location boost profits by adding an online store
d. ) the receptionists at the help desk are collecting the applications.
Step-by-step explanation:
b and c are not correct because "are" in option b should be "is" and the word "is" in option c should be "are". the only sentences with correct verb agreements are sentences a and d.