To simplify the given expression, we start by simplifying the exponent of the first term, which is 3x^0. Any number raised to the power of zero is equal to 1, so 3x^0 simplifies to 3.
Next, we square the simplified first term, which gives us 3^2 = 9.
Finally, we multiply the squared first term (9) with the second term (2x^4), which gives us 18x^4.
Therefore, the correct answer is 18x^4.