Scientists collaborate a lot. The Web of Science tells you who all the coauthors are. Search on Dr. A (Type "Anandakrishnan S" into the author box of the search page). Notice that many of the entries list a few authors followed by "et al." (which stands for "et alia" and means "and others" in Latin). If you click on the blue title, you’ll see a list of all of the authors. So, who was Dr. A co-authoring with in 1994?
A) P. M. Grootes, K. M. Cuffey, and J. M. Bolzan, among others.
B) P. Jung and Q. Old
C) T. K. Dupont and J. P. Winberry
D) W. R. Kapsner, C. A. Shuman and C. R. Stearns, among others.
E) S. R. Taylor and B. W. Stump, among others.

A - P.M. Grootes, K.M. Cuffey, and J.M. Bolzan, among others.

Explanation: Dr. Anandakrishnan collaborated and coauthored with all of the people listed above and has worked with many other people.

During the year 1994, Dr. Sridhar Anandakrishnan collaborated with Kurt M Cuffey, Richard B Alley, Pieter M Grootes and John M Bolzan on the topic 'Calibration of the δ18O isotopic paleothermometer for central Greenland, using borehole temperatures'

They calibrated the δ 18O paleo-thermometer for central Greenland using borehole temperatures, a thermal model forced by a measured δ 18O record and a formal inverse technique. The calibration is determined mostly by temperature fluctuations of the last several centuries, including the Little Ice Age.

Results are generally insensitive to model variables, including initial condition, basal boundary condition, parameterization of snow thermal properties, ice thickness and likely errors in temperature and isotope measurements. Results of this borehole calibration also seem to be in agreement with modern spatial gradients of δ 18O and temperature.

They suggest that calibrations of isotopic paleothermometers using borehole temperatures are a useful paleoclimate tool because they are independent of spatial gradients and include the effects of prehistoric temperatures.