Question:
Which position did William Taylor Copeland hold in May, 1848?

Context:
 William Taylor Copeland holds the position of Member of the 15th Parliament of the United Kingdom from Jul, 1847 to Jul, 1852. 
 William Taylor Copeland holds the position of Member of the 10th Parliament of the United Kingdom from Aug, 1831 to Dec, 1832. 
 William Taylor Copeland holds the position of Member of the 17th Parliament of the United Kingdom from Mar, 1857 to Apr, 1859. 
 William Taylor Copeland holds the position of Lord Mayor of London from Jan, 1835 to Jan, 1836. 
 William Taylor Copeland holds the position of Member of the 12th Parliament of the United Kingdom from Jan, 1835 to Jul, 1837. 
 William Taylor Copeland holds the position of Member of the 11th Parliament of the United Kingdom from May, 1833 to Dec, 1834. 
 William Taylor Copeland holds the position of Member of the 13th Parliament of the United Kingdom from Jul, 1837 to Jun, 1841. 
 William Taylor Copeland holds the position of Sheriff of the City of London from Jan, 1828 to Jan, 1829. 
 William Taylor Copeland holds the position of Member of the 14th Parliament of the United Kingdom from Jun, 1841 to Jul, 1847. 
 William Taylor Copeland holds the position of Member of the 18th Parliament of the United Kingdom from Apr, 1859 to Jul, 1865.

Answer:
Member of the 15th Parliament of the United Kingdom