Select the most appropriate option to fill in the blank.

She is _________ a peacock in the blue satin saree.

The correct answer is as beautiful as.

Reasoning:
In English grammar, to show a comparison of equality (i.e., comparing two things that have the same quality), we use the correlative conjunction structure "as + adjective + as".
In this sentence, the subject ("She") is being compared to "a peacock" in terms of beauty. Therefore, we use "as beautiful as" to complete the comparison correctly: "She is as beautiful as a peacock in the blue satin saree."

Let's analyze the other options:
- "very beautiful as": This structure is grammatically incorrect for expressing a direct comparison between two entities.
- "so beautiful as": The "so... as" construction is typically used in negative comparisons (e.g., "She is not so beautiful as..."). In an affirmative sentence, "as... as" is the standard and most appropriate choice.
- "beautiful like": While "like" can be used for comparison, "beautiful like" is informal and grammatically incorrect in this specific sentence structure without a preceding "is" followed by "like" (e.g., "She is beautiful, like a peacock..."). The comparative structure "as... as" fits the blank perfectly.