The question asks about matters where the Union Government has the power to issue directions to State Governments. This power is derived from specific articles of the Indian Constitution.

The correct matters are:

• 2. Primary education to the linguistic minority in their mother tongue. This is mandated under Article 350-A, which directs every state to provide adequate facilities for instruction in the mother-tongue at the primary stage of education to children belonging to linguistic minority groups.
• 4. Measures to be taken for the protection of the railway within the state. This is provided for under Article 257(2), which states that the executive power of every State shall be so exercised as not to impede or prejudice the exercise of the executive power of the Union. The Union can give directions to a State for this purpose, including for the protection of railways (a subject under the Union List).

The other matters are not areas where the Union has a specific constitutional power to issue directions to states:

• 1. Designing and implementing schemes for the welfare of the tribals. While the Union has a role (e.g., under the Fifth Schedule), it does not have a general power of direction. This is primarily a state subject.
• 3. Promotion of Hindi. While Article 351 gives the Union the duty to promote the spread of Hindi, it does not grant a specific power to issue directions to State Governments for this purpose.

Therefore, the correct answer is the option containing matters 2 and 4.

Related Topics & Formulae

Constitutional Provisions for Union Directions to States: The Indian Constitution provides specific instances where the Union government can issue directives to State governments. These are exceptional powers that override the general federal structure. Key articles include:

• Article 256: Obligation of States and the Union - The executive power of every State shall be so exercised as to ensure compliance with the laws made by Parliament.
• Article 257: Control of the Union over States in certain cases - Specifically, Article 257(2) deals with the construction and maintenance of means of communication (like railways) declared to be of national or military importance.
• Article 350-A: Facilities for instruction in mother-tongue at primary stage - A specific directive principle for linguistic minorities.
• Article 355: Duty of the Union to protect States against external aggression and internal disturbance (a broader, more serious power).

There are no mathematical formulae for this concept; it is based on the interpretation of constitutional law.