The correct answer is D. Hopeful.
Optimistic is defined as having or showing an inclination to believe that the best possible outcome will happen. Hopeful is defined as having or showing expectation of a good outcome. Both words share the meaning of expecting or believing that something good will happen.
Optic is defined as relating to sight or vision. Optician is a person who makes or sells eyeglasses or contact lenses. Favourable is having or showing a positive attitude towards someone or something.
Hopeful is the best synonym for optimistic because it is the closest in meaning. The other options do not share the same meaning as optimistic.