Tessellate S.T.E.M.S. (2019) - Computer Science - College - Set 2 - Objective Problem 5

Suppose $\Sigma$ is a first order language. Say $\mathfrak{A}$ and $\mathfrak{B}$ are $\Sigma$ -models.

Consider the two following statements:

1. $\mathfrak{A}$ and $\mathfrak{B}$ are isomorphic.
2. $\mathfrak{A} \models \phi$ if and only if $\mathfrak{B} \models \phi$ for any first order sentence $\phi$

Which of the following is true?

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This problem is a part of Tessellate S.T.E.M.S (2019)