A

Step 1: Understand the concept of paramagnetism. Paramagnetic substances contain unpaired electrons that can align with an external magnetic field, leading to a net magnetic moment.
Step 2: Analyze the options:
- Iron (Fe): Atomic number 26. It has unpaired electrons in its d-orbitals, which makes it paramagnetic.
- Aluminium (Al): Atomic number 13. It has a full shell of electrons with no unpaired electrons, making it not paramagnetic.
- Nickel (Ni): Atomic number 28. It also has unpaired electrons in its d-orbitals, making it paramagnetic.
- Hydrogen (H): Atomic number 1. While it has one electron, it is typically not classified as paramagnetic in bulk form.
Conclusion: Both Iron (A) and Nickel (C) are paramagnetic, but typically Iron is prominently recognized as a classic paramagnetic substance due to its significant unpaired electrons and magnetic properties. Therefore, we select option A as the correct answer.