Which SPI mode to use?
This figure in the SRAM datasheet shows that the chip reads the data on the rising edge of the clock.



That corresponds to two of your options, I guess the choice between the two is the edge on which the chip changes its output data. The figure below shows that it does so after the falling edge, hence your micrcontroller should read the bit 'on' the rising edge.



There are other SPI configuration aspects, that have to do with the CS line.