Which of the following define linear operators on the vector space $C^1(\mathbb{R})$ of continuously differentiable scalar functions? What is the codomain?
(a) $L[f]=f(0)+f(1)$,
(b) $L[f]=f(0) f(1)$,
(c) $L[f]=f^{\prime}(1)$
(d) $L[f]=f^{\prime}(3)-f(2)$,
(e) $L[f]=x^2 f(x)$,
(f) $L[f]=f(x+2)$
(g) $L[f]=f(x)+2$,
(h) $L[f]=f^{\prime}(2 x)$,
(i) $L[f]=f^{\prime}\left(x^2\right)$,
(j) $L[f]=f(x) \sin x-f^{\prime}(x) \cos x$,
(k) $L[f]=2 \log f(0)$,
(l) $L[f]=\int_0^1 e^y f(y) d y$,
(m) $L[f]=\int_0^1|f(y)| d y$,
(n) $L[f]=\int_{x-1}^{x+1} f(y) d y$,
(o) $L[f]=\int_x^{x^2} \frac{f(y)}{y} d y$,
(p) $L[f]=\int_0^{f(x)} y d y$,
(q) $L[f]=\int_0^x y^2 f^{\prime}(y) d y$,
(r) $L[f]=\int_{-1}^1[f(y)-f(0)] d y$,
(s) $L[f]=\int_{-1}^x[f(y)-y] d y$.