Given: ∑= {a, b}L= {xϵ∑*|x is a string combination}∑4 represents which among the following?

The given question is related to the field of formal language theory in computer science.

Here, ∑ represents the alphabet which consists of 'a' and 'b'.

L represents a language which consists of all possible strings that can be formed using the alphabet ∑.

∑* represents the Kleene star operation which means zero or more concatenations of the alphabet ∑.

So, ∑4 would represent the set of all strings that can be formed using the alphabet ∑ with exactly 4 characters.

This could include strings like 'aaaa', 'aaab', 'aaba', 'aaaa', 'abaa', 'baaa', 'bbaa', 'abba', 'aabb', 'baba', 'baab', 'abab', 'bbbb' and so on.

In other words, ∑4 represents all the string combinations of 'a' and 'b' of length 4.