Correct Answer: EASY
Knowledge: Modal verbs
A. must + V_infinitive: what to do
B. should + V_infinitive: what to do
C. had + to V: what to do
D. need + to V: what to do
But the problem is that it is so easy to “copy and paste” that teachers (10) need to change homework assignments or projects every year.
But the problem is that it’s so easy to copy that teachers may have to change homework or projects every year.
The answer to choose is: EASY