A $4$-bar mechanism with all revolute pairs has link lengths $l_f$ = $20$ $mm$, $l_{\text{in}} = 40$ $mm$, $l_{\text{co}} =50$ $mm$ and $l_{\text{out}} =60$ $mm$. The suffixes $\text{‘f’}$, $\text{‘in’}$, $\text{‘co’}$ and $\text{‘out’}$ denote the fixed link, the input link, the coupler and output link respectively. Which one of the following statements is true about the input and output links?
- Both links can execute full circular motion
- Both links cannot execute full circular motion
- Only the output link cannot execute full circular motion
- Only the input link cannot execute full circular motion