Equivalence of Definitions of Locally Connected Space/Definition 3 implies Definition 1

Theorem
Let $T = \struct{S, \tau}$ be a topological space. Let $T$ have a basis $\mathcal B$ consisting of connected sets in $T$.

Then each point $x$ of $T$ has a local basis $\mathcal B_x$ consisting entirely of connected sets in $T$.

Proof
For each $x \in S$ we define:
 * $\mathcal B_x = \set {B \in \mathcal B: x \in B}$

From Basis induces Local Basis, $\mathcal B_x$ is a local basis.

As each element of $\mathcal B_x$ is also an element of $\mathcal B$, it follows that $\mathcal B_x$ is also formed of connected sets.

Thus, for each point $x \in S$, there is a local basis which consists entirely of connected sets.