MathDB

Some of

A,B,C,D,

and

E

are truth tellers, and the others are liars. Truth tellers always tell the truth. Liars always lie. We know

A

is a truth teller. According to below conversation,

B:

I'm a truth teller.

C:

D

is a truth teller.

D:

B

and

E

are not both truth tellers.

E:

A

and

B

are truth tellers.
How many truth tellers are there?

<span class='latex-bold'>(A)</span>\ 1 \qquad<span class='latex-bold'>(B)</span>\ 2 \qquad<span class='latex-bold'>(C)</span>\ 3 \qquad<span class='latex-bold'>(D)</span>\ 4 \qquad<span class='latex-bold'>(E)</span>\ \text{More information is needed}

Problem Statement