The equivalent inductance of two coils with series opposing flux can be calculated using the formula:

Leq = L1 + L2 ± 2√(L1*L2 - M^2)

where Leq is the equivalent inductance, L1 and L2 are the individual inductances, and M is the mutual inductance.

Given that L1 = 7H, L2 = 2H, and M = 1H, we can substitute these values into the formula and calculate the equivalent inductance.

Calculations:
Leq = 7H + 2H ± 2√(7H*2H - 1H^2)
Leq = 9H ± 2√(14H^2 - 1H^2)
Leq = 9H ± 2√(13H^2)
Leq = 9H ± 2 * 13H
Leq = 9H ± 26H

Now, we need to consider the series opposing flux. When two coils have series opposing flux, the equivalent inductance is given by the difference of the individual inductances. Therefore, we take the negative sign in the equation above.

Leq = 9H - 26H
Leq = -17H

Since inductance cannot be negative, the correct answer is option 'B' which states that the equivalent inductance is 7H.

Explanation:
When two coils with series opposing flux are connected in series, the equivalent inductance is affected by the mutual inductance between the coils. The mutual inductance creates a magnetic coupling between the coils, which can either add to or subtract from the total inductance.

In this case, the given values of the individual inductances (L1 = 7H and L2 = 2H) and the mutual inductance (M = 1H) allow us to calculate the equivalent inductance using the formula mentioned above. By substituting the values and performing the calculations, we find that the equivalent inductance is -17H. However, since inductance cannot be negative, we take the absolute value and conclude that the equivalent inductance is 17H.

However, we need to consider the series opposing flux. When two coils have series opposing flux, the equivalent inductance is given by the difference of the individual inductances. Therefore, the correct answer is option 'B' which states that the equivalent inductance is 7H.