The following program is to be tested for statement coverage:
begin
if $$\left( {a = \,\, = b} \right)\,\,\left\{ {S1;\,\,exit;} \right\}$$
else if $$\left( {c = \,\, = d} \right)\,\,\left\{ {S2;} \right\}$$
else $$\left\{ {S3;\,\,exit;} \right\}$$
$$S4;$$
end

The test cases $${T_1},\,{T_2},\,{T_3}\,\,\& \,{T_4}$$ given below are expressed in terms of the properties satisfied by the values of variables $$a, b, c$$ and $$d.$$ The exact values are not given.
$${T_1}:\,a,\,b,\,c\,\& \,d$$ are all equal
$${T_2}:\,a,\,b,\,c\,\& \,d$$ are all distinct
$${T_3}:\,a = b\,\,\,\& \,\,\,\,c\,!\, = \,d$$
$${T_4}:\,a! = b\,\,\,\& \,\,\,\,c\, = \,d$$

Which of the test suites given below ensures coverage of statements $${S_1},\,{S_2},\,{S_3}\,\,\& \,{S_4}$$ ?

Let $${L_1}$$ recursive language. Let $${L_2}$$ and $${L_3}$$ be languages that are recursively enumerable but not recursive. Which of the following statement is not necessarily true?

Let $$L = \left\{ {w \in {{\left( {0 + 1} \right)}^ * }\left| {\,w} \right.} \right.$$ has even number of $$\,\left. {1's} \right\},$$ i.e $$L$$ is the set of all bit strings with even number of $$1's.$$ which one of rhe regular expression below represents $$L.$$

Let $$w$$ be any string of length $$n$$ in $${\left\{ {0,1} \right\}^ * }$$. Let $$L$$ be the set of all substrings of $$w.$$ What is the minimum number of states in a non-deterministic finite automation that accepts $$L$$?