To find the 12th term of the arithmetic sequence \( U_n = 2, 6, 10, \ldots \), we use the formula for the \( n \)-th term of an arithmetic sequence:

\[
U_n = U_1 + (n - 1) \times d
\]

where:
- \( U_1 \) is the first term,
- \( d \) is the common difference,
- \( n \) is the term number.

From the sequence:
- The first term \( U_1 = 2 \),
- The common difference \( d = 6 - 2 = 4 \).

We need to find the 12th term \( U_{12} \):

1. Substitute the values into the formula:

\[
U_{12} = 2 + (12 - 1) \times 4
\]

2. Calculate:

\[
U_{12} = 2 + 11 \times 4
\]
\[
U_{12} = 2 + 44
\]
\[
U_{12} = 46
\]

The 12th term of the sequence is 46.

The correct answer is A. 46