Given an abstract, indicate which of the provided candidate titles (Option1 and Option2) best describes it (respond with the text of the title, not option1/2).

Example input: Abstract: Some patients converted from ventricular fibrillation to organized rhythms by defibrillation-trained ambulance technicians (EMT-Ds) will refibrillate before hospital arrival. The authors analyzed 271 cases of ventricular fibrillation managed by EMT-Ds working without paramedic back-up. Of 111 patients initially converted to organized rhythms, 19 (17%) refibrillated, 11 (58%) of whom were reconverted to perfusing rhythms, including nine of 11 (82%) who had spontaneous pulses prior to refibrillation. Among patients initially converted to organized rhythms, hospital admission rates were lower for patients who refibrillated than for patients who did not(53% versus 76%, P = NS), although discharge rates were virtually identical (37% and 35%, respectively). Scene-to-hospital transport times were not predictively associated with either the frequency of refibrillation or patient outcome. Defibrillation-trained EMTs can effectively manage refibrillation with additional shocks and are not at a significant disadvantage when paramedic back-up is not available. 
 Which is the apt title for the abstract? option1: Refibrillation managed by EMT-Ds option2: Maintenance of compliance in a small diameter arterial prosthesis.
Example output: Refibrillation managed by EMT-Ds
Example explanation: The abstract is about refibrillation and it is also mentioned in the abstract that it is managed by EMT-Ds. So it is an apt title.
Q: Abstract: Localized regions of mineralization were found in confluent cultures of rabbit marrow fibroblastic cells. The mineralized tissue developed within clusters of giant fat cells in the spaces between the cells. Investigations with light and electron microscopy demonstrated that in these sites there was some differentiation of the fibroblastic cells in an osteogenic direction, shown by changes to more polygonal shapes, and the synthesis of well-banded collagen similar to that found in bone tissue. Differentiation may be due, in part, to increased cell density in a confined space. Growth of the mineralized tissue was observed in the living cultures with a fluorescence microscope. Electron probe microanalysis confirmed that the mineral formed was hydroxyapatite. Initiating sites of mineralization included membranous vesicular bodies, lipid, and products of cellular degeneration. Once initiated, mineralization appeared to spread rapidly into adjacent collagenous and other structures, suggesting the appearance of a mixture of skeletal-type and dystrophic mineralization. 
 Which is the apt title for the abstract? option1: Mineralization in in vitro cultures of rabbit marrow stromal cells. option2: Successful oocyte retrieval and in vitro fertilization following ultrasound-directed aspiration of endometriomas.
A:
Mineralization in in vitro cultures of rabbit marrow stromal cells.