Choose the grammatically correct sentence from the following:

A. The supervisor didn't came out.
B. A stamp often tells a story.
C. The cow is an useful animal.
D. The cat loves a comfort.

Choose the correct answer from the options given below:

B only

The correct answer is option 3. B only.

Let us break down the options:

A. The supervisor didn't came out. This option is incorrect because "didn't came" is not grammatically correct. The correct form should be "didn't come out."

B. A stamp often tells a story. This option is grammatically correct. It is a simple and coherent sentence.

C. The cow is an useful animal. This option is incorrect because "an useful" should be "a useful." The article "an" is used before words that begin with a vowel sound, while "a" is used before words that begin with a consonant sound. In this case, "useful" begins with a consonant sound ("yoo"), so it should be "a useful."

D. The cat loves a comfort. This option is incorrect because "a comfort" should be "comfort." "Comfort" is an uncountable noun, so it does not typically take an indefinite article like "a."

Therefore, option B is the only grammatically correct sentence.