A power/interest grid is a tool for analysing stakeholders based on their level of power or influence and their level of interest or involvement in the organisation or project. The grid has four quadrants: high power, high interest; high power, low interest; low power, high interest; and low power, low interest. The position of a stakeholder on the grid can help to determine the appropriate strategy for engaging and communicating with them. Therefore, option A is the correct answer, as the head of IT services currently occupies the high power, low interest quadrant. This means that he has the authority or ability to affect the outcome of the project, but he does not show much concern or involvement in it. Option B is not correct, as some power and influence and some interest would place the head of IT services in the middle of the grid, which is not a distinct quadrant. Option C is not correct, as high power or influence and high interest would place the head of IT services in the top right quadrant, which is not consistent with his lack of involvement. Option D is not correct, as low power and influence but high interest would place the head of IT services in the bottom right quadrant, which is not consistent with his authority.

References: BCS Practitioner Certificate in BAP Specimen, page 19.