The range of the real valued function $f(x)=\cos ^{-1}\left(\frac{3}{\sqrt{9 x^2-12 x+22}}\right)$ is

$$ \text { Consider the following statements. } $$

$$ \begin{array}{cl} \hline \text { Statement I } & \begin{array}{l} \text { A function } f: A \rightarrow B \text { is said to be one-one if and } \\ \text { only if } f(x) \neq f(y) \Rightarrow x \neq y \end{array} \\ \hline \text { Statement II } & \begin{array}{l} \text { A relation } f: A \rightarrow B \text { is said to be a function if } x \neq y \\ \Rightarrow f(x) \neq f(y) \end{array} \\ \hline \end{array} $$

Then, which one of the following is true?

If $t_n=\frac{1}{4}(n+2)(n+3), n \in N$, then which one of the following is true?

Assertion (A) $\frac{1}{t_1}+\frac{1}{t_2}+\ldots+\frac{1}{t_{2003}}=\frac{2003}{3009}$

Reason (R) $\frac{1}{t_1}+\frac{1}{t_2}+\ldots+\frac{1}{t_n}=\frac{4 n}{(2 n+3)}$