To solve for the digit represented by $\otimes$, we can interpret the symbols as a combination of digits:

Let's break down the equation:

(1) $\otimes + 1\otimes + 5\otimes + \otimes\otimes + \otimes 1 = 1\otimes\otimes$

We consider the value of $\otimes$ and check with each option:

Let’s test with B (3):

Substitute $\otimes = 3$:

$\otimes = 3$ $1\otimes = 13$ $5\otimes = 53$ $\otimes\otimes = 33$ $\otimes1 = 31$ Now, checking:

$3 + 13 + 53 + 33 + 31 = 133$, which matches the pattern of $1\otimes\otimes$ (where $\otimes = 3$).

So, the correct digit is 3.