Answer:
The sentence that contains NO errors is:
C. Due to budget restrictions, no new training courses will be approved until the new fiscal year.
Step-by-step explanation:
Sentence A does not pluralize certificate and spells "receive" as "recieve." It is supposed to read like "Employees will not receive certificates until they have completed all three courses." In Sentence B, the pronoun, "their" should be changed to "they." In Sentence D, "schedule" should end with "d" with the presence of "have been." These leave Sentence C as the only grammatically correct sentence.