Which term of the series 5, 8, 11, 14, ….is 320 ?

The answer is D. 64th.

The given series is an arithmetic progression with a common difference of 3. This means that each term is 3 more than the previous term. To find the 64th term, we can use the formula $a_n = a_1 + d(n-1)$, where $a_n$ is the $n$th term, $a_1$ is the first term, $d$ is the common difference, and $n$ is the number of terms. In this case, we have $a_1 = 5$, $d = 3$, and $n = 64$. Substituting these values into the formula, we get $a_{64} = 5 + 3(64-1) = 320$.

Option A is incorrect because 104 is not a term in the series. Option B is incorrect because 105 is not a term in the series. Option C is incorrect because 106 is not a term in the series.