The correct option is
B The sun shines brightly in the summer.
Option A - 'Brightly' is an adverb and adverbs are usually placed after the verbs. Hence, option A is incorrect.
ofinOption C - As the adverb 'brightly' defines the way 'the Sun shines', it is the subject of the sentence. 'Shines sun' is grammatically incorrect as a verb is never placed before a noun. 'In the summer' describes more about the adverb and the noun here, hence it should be the object the sentence. Hence, option C is incorrect.
Option D - As the adverb 'brightly' defines the way 'the Sun shines', it is the subject of the sentence. 'In the summer' describes more about the adverb and the noun here, hence it should be the object of the sentence. Hence, option D is incorrect.
Option B - 'The sun shines brightly in the summer' is grammatically correct as the adverb is placed after the verb and the descriptive clause 'in the summer' is the object of the sentence. Hence, option B is the correct answer.
'The sun shines brightly in the summer.'