The dimensional formula for surface tension is [MT-2].

Explanation:
Surface tension is the force acting per unit length perpendicular to any line drawn on the liquid surface. It arises due to the cohesive forces between the molecules of a liquid. The dimensional formula represents the physical quantity in terms of its fundamental dimensions, namely mass (M), length (L), and time (T).

To determine the dimensional formula for surface tension, we can analyze the formula for surface tension, which is given by:

Surface tension = Force / Length

Now, let's break down the fundamental dimensions of the quantities involved:

- Force: The dimensional formula for force is [MLT-2], where M represents mass, L represents length, and T represents time.
- Length: The dimensional formula for length is [L].
- Surface tension: The dimensional formula for surface tension can be found by substituting the dimensional formulas of force and length into the formula for surface tension.

Substituting the dimensional formulas, we have:

Surface tension = [Force] / [Length]
= [MLT-2] / [L]
= [MLT-2L-1]
= [MT-2]

Therefore, the dimensional formula for surface tension is [MT-2], which is option 'C'.

Surface tension = force/ length Force = [ MLT^-2] Length = [L] Surface tension = [ MLT^-2] / [L] = [MT^-2]