The correct answer is (a) 2 and 1.
An angular node is a region in an atom where the probability of finding an electron is zero. A radial node is a region in an atom where the probability of finding an electron is zero and the radial wave function is zero.
The number of angular nodes in an orbital is equal to $l$ – 1, where $l$ is the angular momentum quantum number. The number of radial nodes in an orbital is equal to n – l – 1, where n is the principal quantum number.
For a 4d orbital, $l = 2$ and $n = 4$. Therefore, the number of angular nodes is $2 – 1 = 1$ and the number of radial nodes is $4 – 2 – 1 = 1$.
(b) is incorrect because the number of radial nodes is 1, not 2.
(c) is incorrect because the number of angular nodes is 1, not 3.
(d) is incorrect because the number of radial nodes is 1, not 4.