To calculate the wavelength of a wave, we need the formula:

λ = 2π / k

where λ is the wavelength and k is the wave number. The wave number is related to the phase constant by the formula:

k = 2π / λ₀

where λ₀ is the phase constant.

Now, let's substitute the given phase constant, which is 3.14 units, into the formula for the wave number:

k = 2π / 3.14

Simplifying this expression gives:

k ≈ 2

Now, we can use this value of k to calculate the wavelength using the formula λ = 2π / k:

λ = 2π / 2

Simplifying this expression gives:

λ ≈ π

Therefore, the wavelength of the wave with a phase constant of 3.14 units is approximately π units.

Now, let's compare this result with the given options:

a) The option 1 is not the correct answer because the wavelength is not 1 unit.
b) The option 2 is the correct answer because the wavelength is approximately equal to π units.
c) The option 0.5 is not the correct answer because the wavelength is not 0.5 units.
d) The option 4 is not the correct answer because the wavelength is not 4 units.

Hence, the correct answer is option B, which states that the wavelength is 2 units.