### MCQ1: Theory of Computation

Q. In which of the following Regular Expression(s), any number of a's is followed by any number of b's followed by any number of c's is (Indicate all such answers)

```
───────────
Options:
───────────
A. (a+b+c)*
B. a*b*c*
C. a* + b* + c*
D. abc(a*b*c*)
E. (a*b*c*)abc
───────────
```


```
• Points to Remember:
```
1. '*' operator in regular expressions is for 'Iteration' (Matching zero or more specific characters)

2. Regular expressions are used to represent regular language

3. Regular expressions are recursively enumerable or Turing-recognizable languages (Type 0 language)

4. Union, Concatenation and Kleene closure operations can be applied on regular expressions