Upgrade subject to access all content

Which of the followings are maps from $\mathbb{R}$ to $\mathbb{R}$?

Select ALL that apply.

$\{(n,s): s\text{ is the number of seconds in year }n\}$

$\{(x,y): x=y^3+y-1\}$

$\{(x,y):x^2-y^2=1\}$

$\{(\log(t),t):t\in\mathbb{R},t>0\}$