The best way to encourage innovative thinking is not to promise financial rewards for ideas, but to ensure that the person making the suggestion receives recognition for his contribution.
A.
but to ensure that the person making the suggestion receives recognition for his contribution. CorrectB. but to ensure that the person who makes the suggestion will be receiving recognition for his contribution.
Incorrectcontinuous for is wrong, infinitive form required - 'will be receiving'
C.
but rather by ensuring that the person making the suggestion receives recognition for his contribution.
Incorrectparallelism error - ....not to......but rather..., ....to promise.....by ensuring.....
correct parallelism - ....not to......but to...,
D.
but rather ensure that suggestion-maker receives recognition for his contribution.
Incorrectcorrect parallelism - ....not to......but to...
E.
but instead make sure that the suggestion-maker will receive recognition.
Incorrectcorrect parallelism - ....not to......but to...